Minecraft Wiki:Issues/Beta 1.9pre5

The fifth pre-release for Beta 1.9 has been recently released by Jeb.

''' Use the Discussion page first before adding any bugs onto this page. ''' Bugs can be confirmed by checking into the discussion page and make sure other people reply to your report and have the same problem. Please specify if the bug is in singleplayer, multiplayer, or both.

= Issues =

Organization
Please ensure that the bug is tested on a 'vanilla', installation of 1.9pre5 with NO MODS installed

Please specify whether the bug was found on SSP, SMP or Creative and if it is repeatable on other modes.

Please mark your issue with one of these issue labels: (listed from highest priority to lowest)


 * !! = Critical bug that can crash a Minecraft client or server.
 * ! = Major bug. Use this tag sparingly; if there is consensus your bug is not major, it will be downgraded.
 * a! = Major annoyance. Think very carefully before flagging an annoyance as major.  Is it really more important than most minor bugs?  Use this tag sparingly; if there is consensus your annoyance is not major, it will be downgraded.
 * undefined = Minor bug.
 * a = Annoyance.
 * ? = Potential issue that you are unsure of or that the community (on the discussion page) believes requires further vetting.

Labels that Jeb uses:
 * f = Bugs that have been fixed in the next update.
 * s = Bugs that will be skipped/ignored for now.
 * u = Bugs that Jeb tested but was unable to reproduce.

To produce these labels, use the following code:  c where c is the code of the label you wish to use. (e.g., a for annoyances, etc.) Bugs are minor if no label type is entered.

Redstone & Pistons
Redstone is one of the buggiest and most confounding aspects of minecraft.


 * f If a redstone repeater is powered when the player exits a world, upon reentering the world, the repeater will be stuck on the 'powered' state and must be replaced to fix it. (Jeb said on reddit that he fixed this bug. Please confirm by setting to [F].  Thanks!) Should be fixed, yes /jeb


 * f Quitting to title menu while standing on a pressure plate will activate it forever. It must be rebuilt in order to make it usable again, this goes for items on wooden pressure plates too. [Verified] I *think* this is fixed, because I can't reproduce it, marking it as F so you can help me check next update /jeb


 * f Pistons can be used to generate an infinite supply of sand and gravel blocks. Example:


 * f If you build a Gravel/Sand tower(= 3 blocks) on a Piston (connected to a clock) most of the Gravel/Sand will disappear after a couple of pushes. It's fixed, but instead of disappearing they will plop as item instances /jeb


 * f 1.9pre5 data piston bug.jpg Piston combination that upon cycling crashes the game/server. The block on the piston (here red wool) will vanish, but if the block has data value not in the array of a piston (like red wool), it will create an invalid ghost block. Under some circumstances, this wil cause the game/server crash even when trying to reload the chunk. Requires removal of the ghost block with MCEdit and the likes. —AngrySnailtalk
 * Testing now. —Immutetalk
 * Confirmed. Bug produced using precisely the same setup as depicted in image.  Test log:  Turned the lever on; horizontal piston extended, pushing the red wool to the side.  Turned lever off.  Game immediately switched to the infamous "Saving Chunks" screen and became unresponsive.  Restarted the game and attempted to load the world.  As soon as "loading chunks" was complete, I heard a piston noise, and the game again immediately crashed with "Saving Chunks."  I can vouch both for the validity of this bug and its critical status.  Moving it to the top of the Redstone section.  —Immutetalk
 * Fixed, but the design in the picture doesn't generate a pulse clock, if that was intended. /jeb


 * !a!s A piston can be powered by a block that is not directly adjacent to it, but diagonally above or 2 blocks above. However changes to these blocks will not propagate updates to the piston. However, when the piston is caused to update by other means, it will take into account the state of these nonadjacent blocks.
 * When you fix this bug, please also fix "[A!] Pistons should have the connectivity of repeaters"; otherwise, it will be very difficult to power walls of pistons.
 * This may be an 'unintentional-feature' as Jeb has acknowledged this happening before, but also acknowledging that there are many players using this to their advantage
 * Yes I'm not trying to fix this right now because it's a part of certain piston designs /jeb
 * Would you still consider fixing at least one of the [A!] issues below? Thank you very much
 * If only you had had that attitude towards the beloved minecart booster glitch. :P I'm still very much in favor of removing this piston bug, however, (unlike the booster glitch) as it makes building anything with pistons very difficult, since it's so hard to keep all of the odd interactions straight in your head. Besides, if there's a time to make a change like this, it's now.  Furthermore, if you're concerned about breaking certain circuits, you should know that anything currently done with this bug can easily be done without.  For example here is a recently-posted video showing how to make a piston-based block update detector without this glitch.  Finally, I understand the desire to maintain backwards compatibility, but it's not like we have a multibillion dollar industry at hand that relies extensively on legacy redstone circuitry to keep itself running. :D It's your decision, of course, but I respectfully entreat you to reconsider.  Thanks!  :)


 * f In SMP, redstone torches attached to the side of a block in another chunk than the torch itself will sometimes disappear. In cases when the torch's chunk is loaded, but the block's chunk is not, any updates to the torch will destroy it because the game does not see that the torch is attached to anything.  As even the presence of active redstone wire causes the torch to update, this presents a major problem for even fairly simple circuits: most torches straddling a chunk boundary in this way are liable to be destroyed whenever a player enters the area from the direction the torch is attached in.  The details of this bug are better explained and demonstrated in this video:.
 * I thought I marked this as fixed last week? In any case, it should be fixed now. /jeb


 * a! Pistons should have the connectivity of repeaters; a wire running past a piston (i.e., touching, but not leading directly into the piston) should provide power to the piston, just as it would provide power to a repeater.
 * You need to place wire on a block that is touching the piston. This is how redstone circuitry works. The powered wire on the block powers the piston from the powered block.


 * a! A piston placed on top of redstone dust should be able to receive power from that dust. Rationale: It is currently very difficult to power a piston floor.
 * Not how redstone logic works. If you want to make a piston floor, you use the trick with torches powering blocks and the block powering the piston.


 * a! A retracted sticky piston that is being pulled backwards (where "forwards" means "the direction the piston head points") should also pull back the block in front of it, with the restriction that the number of blocks pulled back by a retracting sticky piston shall not exceed 12. This feature was implemented in the last version of the original piston mod after heavy lobbying by the community, and there is no good reason it should not be implemented now.  Under the current system, retracting n sticky pistons takes O(n2) time and O(n3) circuit size.  Under the proposed system, both circuit- and time-complexity would be O(n).


 * f A trapdoor attached to a block powered by a repeater will not react to the power, rendering repeaters to power trapdoors useless and certain designs harder to or impossible to build. If the same block is powered by redstone pointing at it, the trapdoor works as would be expected when powered. Also fixed doors /jeb

Blocks
* I can confirm this. As it has happened many times in singleplayer AND SMP for me
 * f If you make a stone 6x6 square, break the corner blocks, and then try to put a block inside the square, the block dissapears and the block under it also dissapears.
 * f Wooden Stairs drop a wooden plank instead of the stairs.
 * f When a water block is placed with empty space underneath, a column of source block is created under the water block. (Maybe an intended feature? Might help keep oceans from having random holes where land used to be.)
 * f Arrows do not get stuck in lilly-pads. Lily pads are walk-able now /jeb
 * f Enchantment Tables break with a single punch and are destroyed permanently, although they can be mined with a pickaxe.
 * f Save and Quit while water and/or lava is flowing downwards from a high source block can lead to weird freezes in state upon reloading the world (suspended blocks of fluid).
 * f Eyes of Ender will sometimes go to areas without an End Portal. An example seed for 1.9pre4 which suffers from this bug: 1883114686416083372. No seed which reproduces the bug has been found for 1.9pre5. This seed will reproduce the bug on 1.9pre5: -7521364253261532640
 * f Placing a redstone repeater to the side of a jukebox causes a lighting bug on the repeater.
 * f When placing a halfblock of sandstone, and another one under it, then another one over all of them, the blocks combine into 1 sandstone block at the bottom.
 * this happens with every type of slab, has it been fixed for all of them? -Id imagine so. All slabs work the same, the only thing that changes is the appearance via damage modifier
 * f Fence Gates have their collision boxes as the entire cube.
 * fs Glass pane don't connect to slabs, stairs and (wooden?) doors: Fixed the problem with double-slabs, but otherwise they attach as intended /jeb ***make them only attach to the backside of stairblocks ?
 * i believe this also happens with iron bars if it didnt get fixed along with the panes
 * a When waking up in a bed in with a roof made of mushroom blocks, if you wake up standing on the bed, your head will be fully inside the mushroom blocks, and you will begin to suffocate, creating a death loop until the mushroom block is broken. (Does not occur with other blocks; instead you are stuck on top of the bed and can only walk to the sides)
 * f Can place redstone on chests.
 * f This bug has always existed. There is a shadow around glowstone blocks.  There should be none since its supposed to emit light from all directions.
 * f When you break a piece of birch wood you get a normal piece of wood instead of birch (This happens to me i don't know about anybody else).
 * f Fences attach to Chests.
 * f When growing underground tree farms, trees become wooden poles with invisible, glitchy leaves. Leaves do not appear until new torches are placed nearby.
 * s It is possible for a lily-pad to spawn underground and on flowing water. Example:
 * s Flowers can spawn upon sand blocks but cannot be placed upon sand blocks by the player.(Only seen with yellow flowers)
 * s Snow Golems still attack mobs in creative mode in which are neutral.
 * s Dirt blocks that are irrigated shimmer blue on the side when viewed from underwater. Also the water-side of submerged glass blocks.
 * us Tall grass can be generated on dirt and gravel in NPC villages.
 * u Spruce or Pine, when converted into sticks, sometimes cannot be made into tools. This bug is absent with Oak and Birch.
 * u Some signs won't move from a chest to a inventory with shift+click.
 * u ? Enchantment tables aren't affected by bookcases. Not enough information /jeb
 * u a Paintings are black when there is a block above it. Can somebody please verify this in pre-5? I'm unable to reproduce it. /jeb Not happening to me.
 * I fixed It, something was wrong with my client. Sorry for wasting your time, jeb_!
 * ! Minecarts with furnaces can't push minecarts on east/west tracks. This is really annoying after you just dug a 3x3x1k east/west tunnel. Powered minecarts DO work on north/south tracks.
 * ! Whenever chunks are reloaded, animals next to fences can load before the fence, escaping their pens. This may be due to the new fence hitbox.  Since mobs can now be on the same block as the fence post, when the chuck is reloaded, it can be in, on, or outside.  A solution to this could be to record an animal's placement as the nearest block without a fence on it on their side of the fence.
 * s Destroying the block behind a painting will leave the painting floating in the air for a couple of seconds. It's because the painting is an entity that doesn't react on block changes, so it wont pop off until its tick method is run. It's like this for performance reasons. /jeb
 * f Cobblestone stairs drop a piece of cobblestone instead of the stairs.
 * f Stone Brick Stairs drop a piece of stone bricks instead of the stairs.
 * f Brick Stairs drop a piece of bricks instead of the stairs.
 * undefined When using the "Pick Block" function (middle click), it does not differentiate between different blocks with the same ID (such as different colors of wool, different types of slabs, leaves, saplings, stone brick, wood, and tall grass)
 * undefined Also, when using the "Pick Block" function, it does not detect items which can be placed to make blocks (Sugar cane, cake, redstone repeaters, brewing stands, doors, signs, beds, and cauldrons)
 * If anyone else can confirm this I would appreciate it.--CapnDuckface 01:31, 4 November 2011 (UTC)
 * I can totally confirm this, major annoyance of mine since quite some time. Glitchy leaves also means that you sometimes bounce back and forth against invisible blocks. Siebren 07:49, 4 November 2011 (UTC)
 * TheOtherRetard confirms this too. I noticed it when working on a treefarm in SMP. My solution was to dis/reconnect, so I'm thinking this is clientside. I don't know about it in SSP. --TheOtherRetard 17:55, 7 November 2011 (UTC)


 * undefined Glass blocks do not displace loose blocks underwater. What does this mean? /jeb
 * When placing a glass block on a dropped item or item stack it encases the item (the item occupied the same space as the block) instead of being moved to the side. Leaves exhibit the same behavior.
 * Technically speaking, all "transparent" blocks do not move "entities" out when placed over them. Maybe it's time to change the whole opaque/transparent block behavior concept?
 * undefined Creative mode inventory missing items :
 * f Blocks from mods, Items from mods do
 * f 18:1 Spruce Tree's Leaves
 * f 18:2 Birch Tree's Leaves
 * x 18:3 Spruce Tree's Colored Leaves This is not a real block /jeb
 * Same thing as the 44:6 slab, here's a screenshot of that block.
 * s 31:0 Dead Bush placeable on dirt and grass Not adding because it's confusing to have two identical-looking blocks that does different things. Maybe for a later update /jeb
 * f 31:1 Tall grass
 * f 31:2 Fern
 * x 44:6 Alternate Stone Slab (ID 44:6) Not sure what this is /jeb
 * Notice to Jeb: i have posted a screenshot of the alternate stone slab (44:6) and double slab (43:6) on the left, and the normal ones on the right. as the alternate double slab provides an alternate appearance, it would be useful to have for aesthetic purposes. please reassess and change back to [s] or fix. --Gravemind2401 05:47, 8 November 2011 (UTC)
 * s 52:* (Working) Mobs Spawners Would require a new GUI /jeb
 * x 60 Farmland
 * x 78 Snow Plate
 * s 90 Portal Technical block
 * s 97:0 Silverfish Stone Technical block
 * s 97:1 Silverfish Cobblestone Technical block
 * s 97:2 Silverfish Stone Brick Technical block
 * s 99 Huge Red Mushroom Placement not properly implemented
 * s 100 Huge Brown Mushroom Placement not properly implemented
 * f 111 Lily Pad
 * s 119 End Portal Technical block
 * s 120 End Portal Frame Not intended to be placeable
 * However, these blocks are breakable in Creative Mode, and making them placeable in Creative Mode would allow portals to be reconstructed if accidentally broken, and would facilitate travel to The End in Creative Mode.
 * s 263:1 Charcoal Would only litter the GUI
 * x 2267 Music Disc (C418 - where are we now)
 * f Creative mode inventory unneeded items :
 * f 83 Sugar Cane Block - There's the "Sugar Canes" item (338) for that
 * f 92 Cake Block - There's the "Cake" item (354) for that
 * undefined Dead bushes don't get placed in creative mode. I don't understand what this means /jeb
 * undefined Lily pads can now be placed by right clicking on the side of a block 1 space above water, though when placed on vines using this method, the vines disappear. Same happens with mushrooms, though they are just broken. May also work with other blocks, haven't tested this yet Thanks for the info, but what is the bug? =)
 * undefined Cant place a torch on the back of a stair block
 * undefined Very rare, but I have had tall grass generate on water rather than grass. (I don't have a copy of a seed for this, though)
 * f The side grass texture still uses the old dirt texture.
 * undefined Placing blocks on glass and iron bars result in many illegal decorations - tinyurl.com/3s44hx7
 * undefined Some items are not mined fast/slow with the correct tool. These items are:
 * s Wooden slabs are mined with a pickaxe, that's not right! Old bug that is (unfortunately) difficult to fix, so I'm skipping it for now. /jeb
 * A fix to this will be to create a seperate item for wooden slabs, because it's under the damage value of STONE slabs which are mined with a pickaxe.
 * f Fences should be mined faster with an axe
 * f Wooden stairs should be mined faster with an axe
 * f Wooden doors should be mined faster with an axe
 * f Trapdoors should be mined faster with an axe
 * f Ladders should be mined faster with an axe
 * f Crafting tables should be mined faster with an axe
 * f Redstone ore should be mined faster with better pickaxes
 * f Soul sand should be mined faster with a shovel
 * f Fence Gates should be mined faster with an axe
 * f Wooden pressure plates should be mined faster with an axe
 * f Mycelium covered dirt should be mined faster with a shovel
 * f Note Blocks should be mined faster with an axe.
 * f Jukeboxes should be mined faster with an axe.
 * s When breaking melon blocks that are player made you do not get back the 9 melon slices that made it. SSP tested. It's intentional /jeb
 * undefined TNT does not launch the player in Creative mode. [You can fly. Why would that matter?] - It would matter in the case that someone wants to make a TNT transport cannon in creative, where he doesn't take damage and has infinite materials, to later be ported to survival.
 * undefined You can run while in bed. SSP Only. (Multiplayer pops out the chat box, disallowing you to run.)
 * undefined Tall grass isn't "centered" when placed on a block after harvesting with shears. Plainly obvious, has a noticeable overhang when placed on the edge of a higher block.
 * a If a nether portal is placed by the user, it disappears when any adjacent block is changed. This includes placing a second portal block, in which case they will both disappear (After doing a rotation snap if necessary). The portal blocks are obtained using the /give command on SMP. Portal blocks need to be next to a obsidian block in order not to disappear. Otherwise it'll realize that it can't exist there and disappear.
 * Even when placing within an obsidian frame they still disappear. perhaps allowing user-placed portals? (similar to the flag for user-places leaves) --Gravemind2401 01:59, 4 November 2011 (UTC)
 * a While standing in a ladder's block, the ladder tends to be highlighted, making placing and breaking blocks difficult.
 * a If you place soul sand in the ground and have another block 2 spaces above it and you keep walking back and forth underneath you will go through the soul sand.
 * a If you are in bed, you can press shift, and you will be able to see your body, and move your head.
 * ? Chests connect with each other when placed three in a row, with a graphical overlap. When opened, they show the inventory of 2 like normal. How do you place three next to each other? /jeb(@/jeb,placing water first can let you place blocks where they are not allowed-jgchubbyred)@jgchubbyred This was fixed ages ago, presumably you're using an old world from when the water-chest bug wasn't fixed /Ningamer
 * a When shearing vines, the items dropped retain their data values (reflecting which surface they were on when sheared). Further vines in that stack in inventory also have the same data value as the first in the stack.  This causes issues with plugins that don't understand that all data values for item id 106 are vines (most other blocks use data values to distinguish different blocks).  Vines should revert to data value 0 when in inventory.

Crashing
This can commonly be fixed by using the below line in a file ending in .bat or .batch. This works with 64-bit OS machines: "%ProgramFiles(x86)%\Java\jre6\bin\java.exe" -Xmx256m -Xms128m -cp Minecraft.exe net.minecraft.LauncherFrame And this works for 32-bit OS machines: java -Xmx256m -Xms128m -cp Minecraft.exe net.minecraft.LauncherFrame
 * !! Maximizing the window and moving it to another monitor before pressing 'E' or right clicking an interface after starting the game will result in the game crashing with the "Saving Chunks" screen upon pressing 'E' or right clicking any interface in Mac OS X.
 * !! After playing for a few hours an error will occur causing the "Saving Chunks/Out of Memory" error. This often happens while running 32-bit Java on a 64-bit OS. But since 1.9-pre5, it doesn't happen that often anymore.
 * !! Game (clients and ?servers?) cannot tell when it is in distress / running out of memory / processing due to an entity (Mobs or blocks on the ground) overload. Propose that when memory/processing usage is approaching critical levels, the game should take much more aggressive management of entity removal.  This can be achieved in vanilla ssp/?smp? through standing next to a mob spawner dropping mobs into a trap outside the check range but mobs remain inside the "mob reborn" range (this may have been a bug of the above memory leak, the game crashed and I was not able to restart it).  This can be achieved artificially with MCEdit with a 2x2 chunk room 10-20 blocks high and replacing the air with torches or similar.  Entity overload on SMP creative through the use of scripts mass-dropping blocks (before the ability compress blocks into a single unit) is/was a well known and often abused griefing tactic.
 * !! Placing a chest beside a Brewing stand in 1.9pre5 multiplayer will cause it to look like it is not there (transparent), right-clicking on it causes the game to crash. You can still break it without Minecraft crashing. After logging back on the chest will work properly.
 * !! Hitting Alt + F11 causes a crash and a error report to download to your desktop.
 * !! Placing a chest, then removing it, and then placing a sign or enhancement table on that place will crash the client. Tested on CMP
 * !! In the Nether on Survival the game randomly shows the "Saving Chunks" error and crashes
 * !! When you destroy a Monster spawner in SMP in creative OR someone else destroys it in creative or survival the flames don't disappear. If you put a chest where the flames are, it will create a transparent block with a tiny mob spinning inside it. If you right-click the block, your game will crash
 * ? Some users report F11 causing a black-screen crash. I have experienced this before usually fixed with pressing F11 fullscreen glitch possibly happens when in game full screen when to tab out users press F11 this can be avoided by alt + tab to tab out like that - alizter1234
 * Yes this happens to me as well. If I wait too long to switch to fullscreen after loading a world (like more than a few minutes) and then hit F11, it will open a maximized screen that is just black. Alt+tabbing out of it causes minecraft to go out of fullscreen again, but the screen is still just black, and there is no choice but to close it.
 * !! If the game is interrupted by a computer crash unrelated to Minecraft (such as another program running in the background) or a power failure, then the Minecraft .dat file in the saves folder may be corrupted and the world lost. Propose an auto-backup save system similar to that used by MS Office applications. (New save renames the previous save to a backup)

Files

 * f On servers if the ops.txt file is missing the message generated states "Failed to load ip ban list" obviously copied from banned-ips.txt message and not modified.
 * f After loading a world and quitting to the main menu, some region files remain being opened and locked by the region cache manager. Altering these region files requires the game to be fully shut down first, which makes external edits cumbersome.
 * s Saved worlds show up as 0.0 MB. Updating at startup is too slow, and fixing it ingame is too much work... I'm hiding the field instead. /lazy-jeb
 * ! Sometimes after dying on a hardcore world Minecraft fails to delete files and after starting a new world with same name you may find old chunks.

Gameplay
People are exploiting this bug with a program called "Logmein Hamachi". It enables a VPN and people will then play an offline server as though it was online.
 * f Efficiency enchanted picks (tested with Efficiency 4 diamond pick) have little effect on reducing Obsidian mine time. Not sure if intended. Eff. IV should take 40% of mining time - 0.6 x 15s = 9s to mine obsidian.  Not tested..
 * undefined It's not only about obsidian, stone bricks are not affected with efficiensy either. Tested with Diamond pickaxe eff III.
 * ! Occasionally, held items simply disappear never to return. found on SMP, may not be just held items. This is because of the client thinking you still have the item, but the server doesn't think you have the item. To fix this, reconnect or open a container.
 * Test case? I understand it may be hard to come up with one, though...
 * ! Sometimes player will sink through floor; after death problem still occurs.
 * Elaborate please. Otherwise, [?]
 * f Strongholds can be generated without an End Portal. (Sample seed: -7521364253261532640)
 * ! When going into The End, the player turns invisible and the FOV turns all the way up and cannot be turned down. After a little while the screen turns upside down and the FOV becomes increased again.  Yet, the FOV slider on the menu is still at 0, but the game is beyond the maximum setting.  This bug then carries over to all other saves (worlds). Hold N and M and then Y and H (M/N = Roll, Y/H = Zoom)
 * ! Entities can gather up damage from lava in the nether to have it all expelled onto them upon touching dry land (even those entities who are immune to lava damage can amount insane amounts of damage just by taking a lava bath for a few seconds).
 * ! If you put a sapling in a 3 x 1 hole and add bonemeal to it, if a small tree grow, it will make you enter the leaves and you can have an X-ray vision if you look at the wood.
 * !a! Game will sometimes stop receiving events from the mouse and keyboard, leaving the player doing what he/she was doing. (A player walking forward will stay walking forward, unable to change this, not even by pressing escape.)  The only way to get the controls unstuck is to cause the game to lose focus (e.g., by clicking on another window, etc.).  When you return to the game, it will be on the pause screen, as expected, and the controls will work again.  To my knowledge, this is an LWJGL problem, and you can fix it by updating the old LWJGL binaries shipped with the game to their latest versions. This problem isn't fixed by LWJGL update on 64 bit Linux.
 * a! A lot of clicks are necessary to find an specific enchantment level in the enchantment table once there are a lot of books around it.
 * It is notable, this annoyance is the same basic issue with painting's random placement
 * Would be better if the enchantment levels are binomial distributed around the players level, but still capped by the amount of bookshelves.
 * Respectfully disagree; think it would be better if the levels were normally distributed around a number determined by the bookshelf count. Furthermore, the standard deviation of the distribution should vary, say, with the square root of the number of bookshelves. Players often wish to enchant multiple items at once with similar enchantment levels; the other proposed scheme makes this nigh impossible.  Players should use machinery to adjust mean enchantment level, if they wish.  Also, it would be really awesome if the table presented 5 spells at a time instead of 3.  Thanks!  —immute
 * f Block Placement Speed vs Walking Speed: Try walking backwards (or forwards) while placing redstone wire or rail on the ground in a straight line (by holding down right-click). It doesn't work, does it? The rate of block placement is slightly too slow. In my tests, I get segments of 3 placed blocks spaced 1 m apart. Every time I lay down minecart tracks, I am forced to keep backtracking to fill in empty spots or hammer on my MacBook's touch pad, both of which become frustrating fast. The same problem applies to block destruction in creative mode.
 * The fix to this usability issue is very simple: simply change the value of a single constant in the code base... —Immutetalk
 * After some research into the MCP-deobfuscated, source, I am now of the belief that this single constant is actually the tick rate itself, since the keyboard and mouse listening occurs in net.minecraft.client.Minecraft.doTick. While it is feasible to entertain speeding up the tick rate slightly (I certainly think this should be investigated, since if it causes no problems, it would be a fantastically simple solution to this irritating usability issue), I appreciate that this may not be a viable option. (Note: Before you say "But Immute, changing the tick rate will modify the behavior of my circuit," think carefully. The only thing that will change about your circuit is its frequency, unless it is really big and demands an amount of block updates per-tick that the old rate can just barely handle but the new rate cannot, in which case, I'd argue that the behavior of your circuit is already borderline undefined, as its behavior will vary from computer to computer.) —Immutetalk
 * Another choice would be to decrease the walking speed while right-click is held down, but only if the player is not sprinting. By my estimates, the speed should be reduced to 3/4 its normal value. The more I think about this solution, the more I find it to be elegant. While placing blocks, the player cannot exceed in his/her average speed this value anyways. The current practice of backtracking to fill in gaps takes longer than this second alternative, since backtracking requires additional time for changing directions. —Immutetalk
 * s Being suffocated by blocks (i.e. dig down 3 blocks and place 2 sand blocks above you) while in 3rd person will cause the camera to revert back to 1st person. This is due to a anti-exploit, preventing people to see thriugh walls by correctly adjusting their camera. Not a bug /jeb
 * undefined Exploring previously-unexplored deserts in SMP causes the player to run into invisible cacti, which cause damage and stuttering movement. Disconnecting and reconnecting or leaving the area and returning makes them visible.
 * f If you block then click while aiming at a block, then release block, the sword you are holding swings once.
 * undefined If you exit the game (or the game crashes) while in a boat you will start next time on the sea bed with the boat zooming away from you. (SSP. can anyone confirm on SMP?)
 * undefined If you exit the game (or the game crashes) while in a minecart you will start next time buried up to the waist in the ground. If there's lava one block down you'll burn (SSP. can anyone confirm on SMP?)
 * undefined If the game exits though running out of memory or other forced exit while the player is in a minecart, often the minecart will be duplicated on re-start (SSP. can anyone confirm on SMP?)
 * f Impossible to create a world using the seed "0". It will just take a random seed, as if it was not specified. However, we can generate a world using the seed "0" with the server (level-seed=0). 0 is supposed to be identified as "no seed," so I changed the server behavior. / jeb
 * undefined In single-player, leaving an area causes the game to "spike" for a moment, but not when re-entering it. This may be exclusive to the area the user's bed is in. Note: Removing bed does not appear to fix the problem.
 * undefined On the world creation screen, when you resize the window, any name you entered in the editbox will be reset to the default "New World".
 * undefined Similar to the entry above. Minecarts can accumulate damage via high falls.  This damage is expelled onto the entity if the minecart touches a block that doesn't have a track on it (IE cart falls through a 24+ block drop before reaching the player; player hops in and takes a ride; ride leads to a deadend rail and cart skids off the last track; player dies).
 * undefined Sometimes when standing near a repeater you will fall through one level of blocks. (And will sink into the floor up to your waist). Seems to happen more when the ceiling is only 2 blocks high.
 * f The client can place and break blocks 1 block further than the server thinks it can; blocks destroyed this way may reappear. This can be an annoyance for players. The extended reach is usable horizontally but not vertically.
 * undefined Water on top of fence posts can cause entities to hop in place if they move in any direction against a wall 1 block or more higher. This does not happen at all at the .5 minimal height for collision next to water on a fence post.
 * undefined When entering The End, it is possible that you will spawn off the generated blocks and be placed on a 5x5 block of obsidian. If played on a mode other than creative, it would be difficult to make a path to the rest of the map. (gravel/sand?)
 * undefined When playing on multiplayer, a slight lag causes thrown eggs to disappear. Sometimes a phantom egg is placed back in the inventory, also.
 * undefineda You can't hold down the left mouse button to continuously attack any more.
 * undefineda You can't hold down the left mouse button to break a minecart any more. however, an iron sword breaks a minecart in a single hit.
 * f Sugar and Eye of Ender are rendered incorrectly as a tool in 3rd person mode.
 * f Torches cannot be placed on half blocks. As stated earlier, torches can now be placed on full-block halfsteps, but not half ones. /jeb
 * undefined In SMP, the server won't load the End or Nether; therefore making both worlds not generate (the End is just the 5x5 obsidian platform you spawn on).
 * You must dig up from the obsidian you spawn on, you only have to go up 5 blocks.
 * undefined Noteblocks can only be powered in 3 ways, 2 of which is bugged: Direct wire, Torch underneath, and a direct repeater.
 * Firstly, Destroying the torch under the noteblock does not turn off the noteblock. Lastly, The repeater functions backwards, it causes the noteblock to play when unpowered (Sending power does not make a sound, but removing it does)
 * a Armor has very few uses and decays rapidly; diamond armor only has 2x the use of iron, which can disappear after being attacked continually by 2 mobs in less than 10 seconds. Comparison between 1.8
 * f In creative mode, the player often encounters items on the ground. The current behavior of the game is to add these items to the player's inventory, which eventually results in a full inventory that the player cannot empty.  Furthermore, this behavior breaks the "one item in each inventory spot" abstraction that is a core part of creative mode.  Recommended behavior:  When the player picks up an item in creative mode, that item should simply be deleted, instead of going to the player's inventory.
 * a Breaking a door by left clicking the upper portion, a bed by left clicking the half containing the head of the bed, or an extended piston by left clicking the extended wood part instead of the stone base all drop items in creative mode, while breaking any of the previously mentioned blocks by their other "half" correctly drop nothing.
 * f In creative mode, players should be able to fire a bow regardless of the number of arrows they have in their inventory.
 * f In creative mode, an empty bucket should remain empty after being used to pick up fluids, just as a ful bucket remains full. Under the current system, empty buckets are effectively single-use, which can be very annoying.
 * If I'm not mistaken, this was an issue in 1.9pre4, but is already fixed since pre5. Do correct me if I'm wrong. RaizinMonk 16:41, 7 November 2011 (UTC)
 * f In creative mode boats are not infinite forcing you to refill your item bar after placing one.
 * s Unable to put armour on using creative. I would have to create a new GUI for this, but there is not enough time. /jeb
 * f Coal Ore, Redstone Ore, Glowing Redstone Ore, and Lapis Lazuli Ore, all obtainable with Silk Touch, are not smeltable. They are not really intended to be smeltable, but rather placeable for creative purposes... but I've added the recipes anyway for consistency. /jeb
 * To this, I would add that Silk Touch, applied to Glowing Redstone Ore, should yield Redstone Ore, not Glowing Redstone Ore. —immute
 * a cannot use scroll wheel in the mouse to scroll on the world selection screen.
 * a The game has a very slow level income the higher the levels go for enchantments. e.g. You need to kill about 2-4 mobs to gain level 2 when you are level 1, but like 20-40 (guessed) mobs when you are level 20 and want to reach level 21. Since high level enchantments often still result in weak enchantments it's not worth saving levels for them: For example after spending hours and hours of time to get to level 20 killing hundreds of mobs it's kind of frustrating to just get an "Efficincy II" enchantment which will make you save a few seconds mining time in total.
 * This is not a bug, but it is a balance issue. Suggestions get gathered at the discussion page
 * a Not a bug, actually, rather balancing issue. Since there is potion of swiftness II, which makes You run fast and with sprinting faster even then powered cart... There is no need to build time consuming rail lines to cover big distances. So: I think minecarts maximum speed should be doubled, or at least increased to 150% of current max speed.
 * a Powered minecarts have no indication of fuel levels, and are considerably slow, rendered comparatively useless by very few powered track pieces. An increase in pushing power to support 1/1 slopes slowly would help.
 * a Damaged Weapons/Tools cannot be swapped in the inventory for the undamaged ones directly. (Craft new item and replace the almost broken one of the same type you have in one inventory slot. The items should to be swapped the same way they are swapped when you try to place "Axe" on a "broken Shovel".
 * a If in creative mode, and save and quit to tiltle is pressed, when you open your world again your inventory changes to default. But only empty spaces. EX: If you only have Stone Bricks in your hot bar, and you save then re-enter your world, You'll still have the bricks, but also Stone, wood, torches, leaves etc.
 * a Double tapping shift while walking will cause the FOV to muck up
 * This happens while double tapping space as well Cool12309(Talk 23:00, 7 November 2011 (UTC)
 * A more annoying version of this gltich, can sometimes happen if W is spamed.
 * a Trees sometimes grow in ravines
 * a Docking into Soul Sand at boat crashing speeds while on a boat will result in the player taking fall damage.
 * a Signs aren't stackable. (Reason?)
 * a Buckets aren't stackable (but potions were before so it's possible to do?).
 * a Soup isn't stackable (same as above). (Could be a balance issue, but the stack size could be made smaller.)
 * ? Ender Pearls can't be thrown in creative mode.
 * ? Endermen will attack you in Creative mode if they bump into a wall and you are near them.
 * ? Sugar Cane seems to grow at a reduced rate.
 * ? When logging on with a random username and password you can play Minecraft Singleplayer for free. (offline) -- True, but you must have offline (.minecraft) files, then you can log in with a random username. While an offline server would work with this method, an online server doesn't.
 * ? When you're in a snow Biome in Beta 1.9 pre5, if you make a fountain of Water and wait for it to freeze, you can take it with a Bucket, and the next flowing water will turn into Ice.
 * ? While using a bed you will always be interrupted by a hostile mob. (even when the bed is well within a mushroom biome where no hostile can spawn) It seems the buffer distance between you and mobs has been increased to 3? - Are you in a house with double doors? Double doors allow mobs to wake you up unless it is redstone locked.

Graphical

 * f Looking directly at an entity while holding a map will cause the map to become white (see http://imgur.com/5F0Wq).
 * f If you press F3 and exit the world you are playing on, the F3 data/screen will still be visible when you are in the Minecraft menu but you cannot turn it off
 * s Part of the player's skin, specifically the bottom of the head and hat, is facing the opposite direction. Tested in both SSP, SMP, and all the gamemodes. Sorry, but the new alignment is staying. If it's important you need to update your skin. /jeb
 * sundefined Activate F3 and open Creative Inventory. If you scroll down the background of the CPU-Time-Usage-Table (right bottom) disappears. Seems to happen if you see the "Golden Apple" with its graphical effects in the Inventory. //Update: This happens with every animated item in your inventory. Probably just some GL setting that isn't cleared, but I won't spend time looking for it right now. /jeb
 * a! Swimming/sailing in the ocean causes the horizon to flicker obnoxiously (since 1.8). It occurred in the 1.8 update because the water level was lowered one block. Previously, water level was at 65, now it's at 64. When you used to dive into water at level 65, the horizon would turn blue to create that underwater effect. But now when you dive at the new water level, the horizon still behaves as if the water level is still 65, causing that horizon glitch.
 * a! Water and lava drip through and under blocks where it probably shouldn't. Examples: glass, glowstone, wood, signs, and ladders.
 * undefined Some texture overlays on entities, such as glowing eyes, are Z-fighting with the underlying texture.
 * undefined You can do critical hits on: Paintings, Minecarts, Boats, Fireballs, Snowballs, Eggs, Arrows, Other players with pvp turned off, and maybe more.
 * undefined While sat in a minecart wearing armor,opening your inventory shows you sat on your boots as well as wearing them.
 * undefined While in front first-person the fire on the players body while burning is not visible to the player.
 * undefined Swamps have a horrible transition from any biome to a swamp biome leaving some nasty looking colors. Example:
 * undefined Chest armor doesn't move when swinging arms if looking in certain directions.
 * undefined Due to the new camera positioning keys, switching keys (such as I for inventory, instead of E) causes "unintended" camera panning from the player.
 * these keys were left in by accident, and will not be part of the newer versions
 * undefined If you eat rotten flesh and get infected then switch to third person and facing the character the infected animation doesn't play. Tested with fancy graphics and the default texture pack.
 * undefined The wheel texture is flipped upside down on one side of Minecarts.
 * undefined When you die, the player model in the inventory screen also appears dead, blocking some parts of the inventory screen/slots.
 * undefined While you're in bed, the experience level number doesn't fade out.
 * undefined When underwater with the camera position changed, it resizes the blue square filter you get when being underwater.
 * undefined After pressing f6, if you hit left shift to crouch, it inverts your movement controls.
 * If a tree spans two biomes, it may cause an overlap of leaf blocks so that there is contrasting-coloured foliage on the same tree.
 * undefined This is kind of major cause it allows you to look through walls. So what you do is play around with Y,H,N and M, (aka camera angles/depth/etc) then reset it(hold Y and H, and N and M) and press F5. If you are lucky the camera will be screw up and if you look down you will see under ground all the caves. You can't see your character tho cause its like facing the opposite way. Unintended debugging tools left in 1.9pre5. Not a bug.
 * undefined Bucket will not pick up water or lava but still affects the flow. Possibly the effects of switching from creative to survival with an out-dated hack.
 * undefined After using mode switch hack?: Compasses point towards the original spawn point instead of payers bed despite setting it as respawn/sleeping in it. It's supposed to do that... Check here
 * undefined Linked to the Audio Rain glitch, in chunks where the rain sound will not play, you can also see that, while the rain is falling, it does not splash against blocks on that chunk.
 * undefined The 3D Character's Movement in the Inventory screen causes some laptops and older graphics cards to crash (It never happened to me before 1.9.5)
 * undefined Letters do float from bookshelves to enchantment tables even if 'line of sight' is blocked by transparent objects like vines, glass panes, ladders, cobwebs, saplings, ... However, potency of enchantments is not increased.
 * undefined When you punch leaves and look at the sky throught the leaves (on fancy grafical settings) it makes the clouds that you see through the leaves gone.
 * undefined Sometimes a item entities cannot be picked up from the top when a half-block, stair, or fence post is placed on top of the entities. Normally, if an item is floating within a space that is subsequently filled by a placed block, the item jumps to the next air space.  But when the space is filled by a half-block, stair, or fence post, the item appears to jump, but cannot be picked up.
 * Step 1: Make a ring of fences (3x3 with the middle fence post missing).
 * Step 2: Place items in the ring ("place" the items by spamming Q so they are floating entities).
 * Step 3: Fill the ring with the last fence (notice the items jump but cannot be picked up).
 * undefined Alt-tabbing out of the game with the inventory open for extended periods of time (includes doing stuff on other programs) causes all inventory icons to be pitch black upon return. Game looks fine though.
 * undefined You can crouch while laying in Bed, which cause that the camera is inside the player model
 * undefined When you sleep in SMP (not sure about the other modes) the time changes from night to day, but the "time" in game its the same, for example: if you put iron ore in the furnace and go to sleep, the progression arrow will be at the same point.
 * Working as intended
 * undefined Pressing F11 to go into full-screen, and then again to go out of full screen causes the screen to go black. Pressing the Windows key fixes it.
 * undefined Changing the computer's screen resolution in-game causes Minecraft to think it's still in the previous resolution, despite being able to render the full new resolution. For example, loading Minecraft while in 1280x720, then changing the Windows resolution to 1280x1024 will not let you click on the top two worlds in the world select GUI, despite showing them.
 * undefined Drops fall 'inside' glass blocks and glass blocks can be placed over drops & items without them 'popping' out into the nearest air space. Also sometimes happens with fence posts in which case the items can appear black.
 * undefineda while in 3rd person mode and the player is in water, the screen turns blue even if the camera is not in the water
 * undefineda having transparent areas on player skins causes the area to turn black. this is very annoying for "floating head" type skins, headless ones, and legless/armless ones. (however, if the default skin is replaced inside the minecraft jar file, it shows transparency properly)
 * This could possibly be to prevent players from picking fully transparent skins and run around causing mayhem. /Kevdama
 * i was thinking that too, perhaps disallow fully transparent, but allow the headless/floating head etc type skins? /Gravemind2401
 * a If you had smelted some iron or whatever and they are done, you dont see any difference in the texture of the furnace. When you have many of the furnaces, there could be some items left in the output-box. It would be better if you could see without looking in it, whether there are items smelted or not

Lighting

 * f Glowstone behind glass is odd, the light shines through but the glowstone itself is almost black. Example:
 * f Redstone Repeaters placed between two full blocks are dark when placed along Z axis. They are properly lit when placed along X axis.
 * u Chests and signs are often black or very dark even when in a well lit location I can't reproduce this in pre-5, can you show me exactly how you build to make the chest dark? /jeb This only happens when using certain Intel graphics chips.
 * Occurs much more frequently on chests from an older world (that is, chests placed before the chest graphics update).
 * u Enchanting Tables Books are often black or very dark at some angles What angles? APPLY SCIENCE! =) /jeb Same as above
 * ! On many Mac OSX systems there is harsh visual lag, and you can see through blocks partially (not due to textures) as well as at night the lighting inside is blue as well as odd strips going through blocks -this is probably caused by the power pc processors that apple used in old models, just as there were graphical bugs in ppc macs in every versions before beta 1.2
 * ! This lighting bug is better explained by a short, voiceless video here [Skip to 1:20 for the bug; earlier shows how to create].
 * ! not only that but there are bugs letting you see through blocks when it is dark even in smp
 * undefined Repeaters do not respond to light level increases. Test case 1:  Place repeaters on ground at night.  Go to sleep.  Repeaters will still be pitch black, even though in direct sunlight.  Placing blocks nearby forces them to update.  Test case 2:  Place repeaters on ground in a dark area.  Place a torch nearby.  Repeater stays dark.
 * undefined Arrows shot at the bottom of a block appear dark, even in well lit areas.
 * undefined Black an white flickering on chests and all placeable objects on Minecraft Windows 7. Occurred since 1.8 // cannot reproduce.//reproducible, same with WinXP//same as above (?)
 * undefined Black and white flickering on all mobs and the player arm when playing Minecraft on Windows XP. Has occurred since 1.8 // cannot reproduce.//reproducible, maybe only with Intel graphics chips?//reproducible on an ATI Mobility Radeon X1400. // Happens on my friend's Vista. Probably to do with graphics card instead.
 * undefined Glowing redstone ore appears darker if light level is high Redstone block lighting.
 * undefined If the block adjacent to a water source has a lighting issue, the bubble particles will become black.
 * undefined If there is a block directly behind glass, it appears dark even though light should pass through the glass.
 * undefined Light does not pass through holes in walls made by half blocks. Example
 * undefined Light source is placed underwater and destroyed the light stays. - Fixed in the newest Pre-release.
 * undefined Occasionally some leaf blocks on trees that become enclosed later will continue to generate somewhat dim sunlight (light level changes based on night/day cycle). Forcing a lighting update doesn't fix, only destroying the block will. Examples:
 * undefined Paintings are black when there is a block above it.
 * undefined Signs flicker dark. //maybe only with Intel graphics chips?
 * undefined Some torches generated in abandoned mine shafts or NPC villages don't light anything up, unless replaced or if another torch is placed by it.
 * undefined Sometimes overhangs create pitch black shadows, as shown here File:2011-10-27 16.52.37 copy.png. However, when one gets closer to the cliff, the lighting is updated and the pitch black shadow disappears (as shown here File:2011-10-27 16.52.51.png).
 * undefined There are some random lighting errors when a world generates, such as block with a light level of 1 under certain parts of a cliff, or sometimes random blocks on the ground in daylight are black, and standing on them makes the character dark too. This can be fixed by right-clicking the block while you are on it. (It's still annoying though)
 * undefined You can see chunk boundaries 'under' ice on some systems. // This might be just on Fast graphics. Someone test it!
 * undefined light "leaks" through the corners of stair blocks: example image
 * undefined Swimming wolves are very dark. Totaly black at night. The lighting flicks between light & dark as they bob in the water.
 * undefined light does not make it into the gaps in slabs and stairs if there are blocks on all sides: example image

Maps

 * f Using a map, while in a boat, at night, causes the map to become "highlighted" when the player looks down at the map.
 * u Map arrow don't match real looking direction. // Confirmed. This happens in my game, the arrow is often 1 direction to the right of where I'm looking.
 * (To reproduce: Get a map, save and quit, reload game, rotate left. - There is a deadspace for the this turn where the arrow doesn't match-up...if you then turn 100x to the left it will take 101 times to the right before your arrow syncs up. Also if you turn right it will never go out of sync.  Seems to be a rounding or zero error.  Facing south, a right turn of ~16° ticks the arrow, however it takes ~35° when turning left)
 * u All maps made will center on the location where the first map was created.
 * Pretty sure this is just the shift click craft bug Mug806 16:05, 7 November 2011 (UTC)


 * ! When you are flying on ice, you will see the sides of the chunks (Confirmed for versions 1.6, 1.7.3, 1.8.1, and 1.9pre5)
 * ! Created a map prior to 1.9pre5. After getting 1.9pre5, every new map made is an exact duplicate of the first one regardless of where it's made. Check and make sure you're not holding down shift when crafting the Map; this will always create a duplicate of "map_0"
 * ! Sometimes maps will cut off chunks and replace them with endless oceans.
 * a Blocks which use damage values to select their appearance only show the default color on a map, e.g. an area full of red wool will show up as white on the map. It's because blocks uses the material color in maps, so it also happens with blocks that do not use damage values.
 * It would also be nice if a single colored wool block would override the color of a map pixel, so that markers can be easily created (or maybe 5 wool blocks in a X or + shape?)
 * a In Creative mode, the map origin is always at the spawn point, independently of where in the world the map was held for the first time. The only work-around is to actually craft a map every time you explore a new area, but that defeats the purpose of having a map in the Creative mode inventory.

Mobs

 * f Endermen may teleport after the player deals a killing blow resulting in their drops appearing elsewhere, often out of sight of the player and therefore lost. Confirmed, using iron sword on SMP, though drop was never located. Also confirmed, though I hit the enderman at a really precise time and I saw his experience orbs fly far away.


 * f Sheering baby Mooshrooms yields a full grown adult cow rather than a baby cow. Possible exploit to gather beef faster from breeding by bi-passing the time spent to age.


 * f Slimes and Magma Cubes do not despawn when setting to peaceful despite being hostile mobs at all sizes. This is indeed a "feature" but it was also not as intended when originally coded.  The original intent was to allow the smallest version of them to spawn but remove the rest since the smallest ones do no damage, just annoy.  This clearly is not how they have been behaving all these months.


 * f Spiders, Endermen and silverfish will still try to attack you even if you have not provoked them in creative mode (other hostile mobs do not ).


 * f The cow, pig, wolf, sheep and sheep fur rear texture are upside down. It's maybe a general bug and maybe concerns all mobs/items/entities like boat, cart, chest and sign... It does affect the underside of player's head (1.8.1 was fine, during pre5 I noticed the bottom of my chin was now at the back of my neck; not sure when it started). Fixed by updating the skins /jeb


 * f When trying to feed pigs with saddles wheat, it does nothing, and instead just mounts them.


 * f Slimes and Magma Cubes are voiding several spawning algorithm rules. Such things as spawning on top of blocks labeled in the game as non-spawnable (glass, half steps, stairs, etc.); spawning inside of translucent blocks next to air blocks, such as spawning inside of a piston block; spawning inside 1x1 block spaces that contain translucent blocks such as redstone, repeaters or torches.
 * After more research and testing, I have found this is caused by them ignoring the collision mask for translucent blocks. I've witnessed all sorts of weird stuff like them spawning inside of extended sticky pistons holding solid blocks and unable to move because of the pushers collision mask; spawning inside of glass with a solid block below it; spawning inside of extremely tight spots because the head layer was glass or piston and spawning on top of things like repeaters, half steps and the like when they clearly have a collision mask.  I could not replicate this with any other mobs, so the mistake lies somewhere in the code for cubed entities.


 * u In a dark area, creepers and skeletons don't attack you. Creative mode? /jeb No, I had it today the first time, a zombie spawned near my bed, because I forgot to lit up the hole I dug. He punched me out of the bed, but after that he did nothing more. /Wieherbuh


 * u Chicken clips through gravel block and asphyxiate while following the player with wheat. How? I'm unable to reproduce this /jeb The easiest way I've found to reproduce this is to spawn a massive number of chickens with eggs in a confined space, and eventually the chickens will kill themselves through suffocation. not exclusive to gravel, though.
 * Chickens seem to take damage when wedged between a corner of 2 blocks. Noticed this in chicken pens, as well as when they follow you up a mountain with wheat. Might be related to water "flowing" through corners of blocks. Spawn many chickens in a room and watch the corners of the walls. /Agnate


 * ! When jumping, all mobs (especially slime) glitch through floor below them/ceiling. This happens only on SMP because of the different mob collision mechanic. This can be exacerbated when multiple mobs are confined to a small location, but it can happen with a single mob as long as it jumps in the confined space (ex: a mob stuck in water often displays this behavior). When they jump, they appear in the compartment above them but are invisible and can still attack the player in the compartment below.  For invisible slimes, this is accompanied by their sound, slime particles, and pushing.  If the player swings at the empty space where the pushing occurs, the player may be able to kill the mob, but it's mostly luck to hit it in the first place.  To recreate this bug, connect to SMP, go to a chunk that spawns slime, build a two-level compartment and observe how the slime "teleport" between compartments when they hop.


 * ! All (non aquatic) passive mobs make a bee-line for the sea. After a short while the land will clear of livestock which can be found floating offshore or trapped in ponds and pits. Includes cows, pigs, sheep & mooshroom cows. Chickens seem less affected. (confirmed on SSP)
 * ! More generally, it seems that as time approaches infinity, all animals eventually walk into unloaded chunks and get stuck there. The above bug seems to be a special case of this
 * This may be due to mob pathfinding directing them to attempt to reach a point below them. I have witnessed chickens climb a dirt spiral to jump and float out of a pit, so this may be a case of the pathfinding algorithm trying too hard to move in a direction.--PlNG 20:28, 29 October 2011 (UTC)
 * On my SMP all the animals get trapped, either in a lake, or on a single block on the side of the a cliff they cannot jump back up from.
 * I have upgraded this to [!] since it, in combination with animal persistence and the ridiculously low passive mob cap, makes getting animals really difficult.
 * Suggested fix: Make wild animals despawn/respawn as they used to, but once bred/tamed they are triggered into a "no-despawn" state. This would enable the player to keep which animals they want, but stop wild animals from accumulating in caves and water holes. cal-erstein


 * ! Mob path-finding is rather buggy and can easily break in tight spaces. In fact, even a single block placed well over 50 blocks away has a chance to cause mobs in a tight space to behave blatantly wrong, typically resulting in mobs ignoring the player entirely.
 * For example, creating a 2-wide, 2-tall, 3-long corridor, placing signs on the top 6 (head level blocks), and placing pressure plates on the back and front two floors (leaving a 2-wide gap) has resulted in pursuing zombies getting stuck in the center bit, ignoring the player.


 * ! wolves have practically vanished from the game, because they despawn when untamed and then never respawn


 * a! No more wool produced by sheep after a single shave. Tester this bug on multiple machines on SMP and SP.
 * Not a bug, but a major annoyance.


 * undefined Mooshroom spawn too much in some area (see http://tof.canardpc.com/view/993ab614-4193-4b24-9d04-fcadd5c3f517.jpg). More than 29000 was removed with the help of MCEdit. The Mooshrooms spawned back after several minutes.


 * undefined Mobs, in general, spawn in huge amounts upon certain chunks in SMP. (Example: All the mobs suddenly disappeared and the server started to lag badly, after using a mob finding program I found a chunk with bazillions of sheeps, after killing them, the lag disappeared, I have no idea what causes this, sorry.)
 * Could you please be a bit more specific so that Jeb can find the bug more easily. Thanks!  :)  —Immutetalk 23:45, 6 November 2011 (UTC)


 * undefined Skeletons don't wield their bows with two hands anymore.


 * undefined Chickens disappear once they mature into adults. Doesn't happen for me. Instead parent chickens follow the baby even after maturity), But if chickens take damage such that from being hit with an egg) they stop following the matured Baby. - Happens with all farm animals, see below.


 * undefined farm animals may follow their babies even when they are grown up which can lead to large 'animal balls' (confirmed on SSP) Quitting and restarting Minecraft seems to fix this behaviour until they breed again.


 * undefined farm animals will continue to follow their 'desired' mate partner if they weren't able to mate (happens when the 'desired' mate partner mates with another animal) [SSP]


 * undefined When a chicken focus on the player, it moves its head down instead of up like other animals/mobs.


 * undefined Passive mobs constantly bounce when next to fences even though they cannot get over. (confirmed on SSP) This eventually results in their death over time as they clip into blocks momentarily and suffocate. Over time they accumulate enough damage to die. All penned animals do this and die over time. Following bugs are related or the same issue.
 * undefined chickens seem to have an additional bug and suffocate while jumping down from a single block height. (seen in smp)


 * undefined Dragons break any block they touch. i know this intentional, but are they supposed to be able to bust bedrock as well?
 * Fear not, intrepid miner, for there is no bedrock in their native realm.
 * oh but there is, what if someone were to make a bedrock shelter in creative mode? also, i thought notch was also planning to have red dragons in the normal world eventually.


 * undefined You can see see mobs far away in fog, though they are white.
 * Correction: you can see Endermen and spiders far away in fog.


 * undefined Endermen survive in sunlight. Intended, not a bug.
 * undefined Mobs don't spawn in hardcore mode if one switches from peaceful difficulty to a hardcore world.
 * undefined When the player walks into a fence's blockspace, aggressive mobs do not detect the player and will wander aimlessly
 * undefined Cows sometimes spawn in trees. http://img6.imagebanana.com/img/8zulqcbk/20111106_16.47.20.png


 * undefined I found a bug that make animals mobs such as cow and sheep kinda glitch to the surface if they are underground that makes it kinda annoying to have a underground farm the glitch seems to occur when they are underground and the surface is blocked by only 1 block.
 * undefineda Chickens kill themselves and/or each other in confined spaces. Makes breeding chickens in a pen almost impossible.
 * ? Ghast hit box (and collision check when spawning) are set approximately one block too low.
 * undefined in SMP a skeletons arrow occasionally bounces off of players

Multiplayer Related

 * u From pre4 thread: "Blocks are not always what they seem to be. For example, a Dirt block can look like a Stone block.". It seems that the cause is that the client got one chunk with wrong data since it can be fixed by rejoining the server. The bug is very rare and very old (at least a half year). For video evidence of this, or a bug related to this, see at time index 23:10.  This video is from Beta 1.2_01 and doesn't depict the exact manifestation of how this bug appears now.  The video linked shows a diamond block appearing as stone.  Once broken, it is reformed as a diamond block, which could then be broken into a diamond item.  This is slightly different than how it manifests now, which is, that the diamond block would appear as stone, only to break into a diamond item without the intermediate diamond block being reformed.
 * ! Endermen are not aggressive during the daytime when looked at and this also can happen at night and underground.
 * Elaborate, please.
 * ! Reducing server.properties view-distance drastically reduces/eliminates mob spawning in SMP
 * ! Spawn point in The End seems to be related to the coordinates of the portal in the overworld. may result in spawning ~1500 coords from the origin on the X-axis. see discussion page for more info. (if you are in survival mode, you have no way of getting to the normal area)
 * ! Players with slow internet connection can only hit mobs with melee attacks on the head. This is not exclusive to 1.9, as it goes back at least to 1.7.3.
 * a! SMP worlds are not saving properly, when a server is restarted some areas are either newly generated or else a 'bugged out' and are spliced with what I assume to be the sky world. This creates a very uneven surface area with massive drops such as: Example
 * undefined When exiting a minecart after riding it, the player floats and can clip into blocks. This condition only disappears when restarting the Minecraft client. This also happens in some cases where water is flowing down on top of you and you place a block above yourself. Restarting client (rather than reloading world) confirmed to resolve this.
 * undefined When an arrow is shot at a block, the shot arrow floats to the top of the block. It does not stay at the position it was shot at.
 * I can confirm this. It makes the whole smp experience feel very unpolished.
 * undefined Throwing a full stack of items on the ground results in throwing another "ghost" stack right after it, leaving two stacks (one stack are the real items, other stack are the ghost items)
 * undefined There are some missing animations and broken features in singleplayer that are not working in multiplayer:
 * Creepers do not puff up when about to explode.
 * Minecarts and boats do not wiggle when getting destroyed.
 * Endermen do not attack when they are looked at.
 * Endermen do not shake when they are looked at.
 * Critical hits do not do extra damage and its animation does not appear to you or any other players.
 * All mob spawners have a pig inside them.
 * No sound is heard when a skeleton or a player fire an arrow. The arrow sound when it hits a block is still heard, however.
 * (Add any more when found)
 * undefined Starving to death while riding in a minecart in the nether causes an Internal Exception and kicks the player from the server
 * undefined Query protocol reports "hostname" key twice while first one is "motd", and the second one is ip the server is running on. First occurrence of "hostname" should be replace to "motd".
 * undefineda Not a bug per se, but there is no flag in server.properties to allow/disallow travel to The End in SMP. (like the "allow-nether" flag)
 * undefineda Use of multiple TNT on SMP occasionally leaves 'ghost' TNT tiles (old bug, been around since as far back as 1.2.3_04 as per YouTube video). This is a client end issue, as re-logging will typically remove any ghost tiles.
 * undefineda Similar to TNT issue, when clearing high pillars of sand/gravel from the base up, some times you will encounter this problem, too.
 * undefineda Enchantment : The enchantment animation can not be seen by other players (tested on multiple machines).
 * a There are some lighting glitches such as: Destroying a block leaves a light level of 1 at the location the block was destroyed, repeaters are sometimes black.
 * a Servers could use join/quit DDOS/flood protection through queuing, or at least the ability to limit/combine/reduce player announcements.
 * a Whitelist toggling in the console doesn't appear to do anything. whitelisting seems to work, but requires a restart to activate/deactivate
 * a /kill doesn't work if you are in creative gamemode.
 * a In SMP, mobs are too dangerous, especially creepers, where they explode even when they are very far away from the target. It takes a while for them to realize the distance b/w them and the player.
 * a Slime mobs, maybe magma slime either, move in very annoying way, the bounce rapidly up and down, and tend do clip over a ceiling/floor. this happens mostly with the tiny slimes,sometimes with medium, never noticed with big slimes. When they appear to clip over the ceiling, their collision frame is on the upper floor AND lower floor simultaneously, however, they attack can occur only on the floor they actually are. This makes them very difficult to kill, because player never knows, where they really are. This bug occurred in earlier versions (1.7, maybe earlier), but since slimes start to occur on upper map levels, it made them really annoying.
 * a Nether Portals : Same bug as portal to The End (Portal is created above a huge lava lake, land is far away)
 * This is a side-effect of the portal generation system. The game compensates for this by generating an obsidian floor to stand on and it is not one-way like portals to The End.

Memory/CPU General

 * undefined The Macintosh version uses 32-bit Java, even on 64-bit computers (This is because the launcher specifies 32-bit java, but there is a fix that requires Xcode and very precise changes to the application package.) For a simple alternative to launch Minecraft in 64-bit Java, use this terminal command:
 * java -Xms512M -Xmx1024M -jar /Applications/Minecraft.app/Contents/Resources/Java/MinecraftLauncher.jar
 * Same here, on Windows 7 64bit, unless you use a batch file, or shortcut:
 * "C:\Program Files\Java\jre7\bin\javaw.exe" -jar "full path to minecraft.exe"

Sound

 * undefineda! Sound mixing problems. Note blocks are way too quiet; I can barely hear my notification chimes over the sound of nearby cows.  Doors, cows, way too loud.  Portals way too loud; also portal noise should drop off with distance much more sharply (certainly not in a linear fashion).
 * undefined Some mobs (specifically zombies, as far as I can tell, but there may be more) have a tendency to make noises right after they are killed. Try this test multiple times: Spawn a single zombie and attack it.  A couple of times, you'll hear a regular (non-damage) zombie moan/growl  up to tens of milliseconds after the zombie dies.
 * undefined Unchecked volume increase? Placing a water source at the feet of 500+ mobs standing in a single square produces a very loud sound equivalent to a small army of creepers detonating simultaneously.
 * undefined Walking across a series of trapdoors does not make any sounds. Walking across the edges of blocks adjacent to the trapdoors (i.e., walking across the top of the block containing the trapdoor) makes the walking on wood sound.
 * undefined Lightning can sometimes be heard near bedrock
 * Likely intentional. Lightning is supposed to be loud. /Kevdama
 * undefined All sounds lost in general apon startup of minecraft client takes a couple of restarts of the client to fix this. Having a debug option like F3+S to reload all sounds might work. Happens on unmodified versions of 1.8.1 1.9pre-4 don't know if it is fixed in 1.9pre-5. Never had this problem before 1.8.
 * This happens for me too on 1.9pre-5, but only on Windows, not OS X (on the same machine).
 * I had this problem too. Something I did fixed it, don't remember what.
 * On ubuntu 11.10, this sound loss occurs when some other app is using the sound output device when Minecraft is started, like when watching a youtube video in a Chrome tab.
 * undefinedFlying into a Fences stacked more than 1 high somewhere in the middle makes a sound like you're walking on wood when you're still flying.
 * ? Rain does not always generate the rain sound.
 * ? chest do not make opening or closing sound next to stone blocks.
 * It hasn't made the open/close sound at all in 1.9. Fairly certain there's a new sound for it that hasn't been added yet. /Kevdama

Weather

 * undefined Sometimes a thunderstorm can start but it will not rain until near the end of the storm. Mobs spawn normally.So? That's what happens in real life, it just makes it more realistic
 * a Weather sounds/looks the same regardless of weather severity. Would be nice to be able to distinguish audio/visually between an overcast day, a light drizzle and "Get the **** out of this!" weather. Thundersnows and Desert Lightning.
 * suggestion for next versions: sandstorms in the deserts | Suggestions should be posted in the suggestions page. not the bug page /I_Lag_Badly
 * ! If the user is playing on a map generated before 1.8, every water may freeze over because of ice regeneration in the newly generated snow biomes even if there is no snow there.

Lava

 * f You can now create an infinite lava spring.
 * a! Lava creates small half-source blocks when it flows downwards. These sources constantly produce lava even when it is cut off from its main source block, and cannot be grabbed with a bucket. These properties make it very frustrating and difficult to clean up.

Water

 * !a! if you have a column of water running down a wall and you block the hole, the water below it keeps flowing, it's like all the water becomes source blocks. //Confirmed, water placed above air will turn all blocks below into source blocks. This makes it impossible to have 1x1 flows of water because the source blocks will leak in all directions. this should be made so that only source blocks placed above air produce source blocks under it and non-source blocks produce non-source block water under them (like when a stream flows off a cliff from a source block placed on the top of the cliff)


 * undefined Placing a contained water source next to a ladder then carving the block below the ladder and placing a source block in that position will cause the first source block (the one next to the ladder, not under it) to convert into a flowing stream that points at the ladder; or rather the source block hidden in the hole below the ladder. Unsure which the game is doing since they are both in the same direction using this trick.  Basically it turns a source block into a flowing block when it shouldn't.


 * undefined Tunneling up into the side of a body of water, finding yourself in a 1x1 waterfall and placing a block above to block the water caused no clipping (limited to the horizontal plane). Possible to move into blocks (causing suffocation) and resolved be quitting the entire client and restarting (exiting and reentering world does not resolve it). Probably an F6 issue /edit Confirmed.


 * undefined Fluids such as water can alter other fluids to change their angle; however the angle of the water can alter whether or not an entity can jump out of the water. (Further explanation: Prior to 1.6 this feature didn't affect the way the water reacted with entities.  Current tests to exploit the angles of waters in all 4 directions when water was applied to corners or head on to shift the angle caused varied results.  For instance, it is impossible to jump out of a source block onto any other source blocks 1 block higher.  Using flowing water yielded a rather varied slew of results.  With just water straight ahead in the direction being tested, only West was able to hop out into the source block.  With water applied to the corners of a flowing stream to lift it up, 2 directions could hop out onto a dry block just fine while the other two could not.  All tests were done on the player, but I noticed these problems several months ago on a mob machine and did a slew of tests using mobs to gather the same odd results.)


 * undefined Using silktouch to obtain ice allows you to place water in the nether.
 * so does a bucket of water, this isnt really a bug.
 * Well, not really, water placed with bucket evaporate immediatly. However, iceblock sourced water is not a bug - it's a feature. Water collected this way, cannot bed easely multiplicated.


 * xa Water doesn't push activated TNT or minecarts.


 * xa Falling water destroys items normally pushed aside by flowing water. An exhaustive list: Sapling, powered rail, detector rail, cobweb, tall grass, dandelion, rose, brown mushroom, red mushroom, torch, redstone wire, seeds, rails, lever, redstone torches, button, redstone repeaters, stems, lily pads, nether warts, and other objects of similar nature.

Biomes/Dimensions

 * ! the spawn point in The End may sometimes be located off the island, so you can only get there with creative (or if you have enough blocks to make a bridge). this is similar to (but not as severe as) the spawning issue noted in the "Multiplayer Related" section


 * a! Strongholds almost always have mineshafts or canyons generated through them, usually taking out large chunks of what would have been the stronghold. this may be what causes some strongholds to have no portal.


 * a! The biome boundary between swamps and other biomes are just completely UGLY and don't blend in AT ALL. You should make it so the color of the swamp biome's grass should fade out when coming in contact with another biome's grass. Same with the water.
 * I don't think this counts as a bug, and im sure jeb has more important things to fix before minecon.
 * It is a bug. Notice how there's always a gradient in the grass color at every biome boundary, except those involving swamp biomes.  Clearly, swamp transitions were left out by mistake.    If there are any "bugs" in this section that need to be downgraded, it's those involving migrating from 1.7 to 1.8; Mojang explicitly stated that they were deprecating old terrain.
 * I stand corrected. and i agree on the transition complaints, its annoying.
 * I agree, looks horrible.


 * a Swamp biomes are way too common


 * a In creative mode, getting underneath the end portal and looking up does not display the end portal effect. The portal can also be broken when punched, leaving holes when seen from above.
 * correction: the portal blocks are see-through from below in either mode - i think this was intentional. in creative mode you can break any block, portal or otherwise.
 * Why would you think this is intentional? Nether portals are visible from any angle.  It makes no sense to assume that the end portal should only be seen from above since you can walk around and see under it without breaking any blocks.  Bug.


 * a there is still no way to leave The End (without dying) as of pre5. (has it been fixed for 1.0?) // Personally, I don't think this will be fixed. Think of the challenge The End provides if you can only leave by dying. //well without being able to return to earth and gather supplies, and with the End only being one single island, having no return makes it seem kind of pointless to go there in the first place. especially on hardcore or on survival if you want to mine some end stone or obsidian Mojang have explicitly stated that The End isn't finished. Having no exit is not a bug, it's an incomplete feature.
 * suggestion: seeing as the portal to the end is a sort of space-like effect resembling the sky in the end, perhaps the portal back could be blue with clouds resembling the earth sky
 * or could it be made so that once you defeat an enderdragon it becomes tame and you can ride it out of the end and into the normal world?
 * or you could save feature requests for other pages, this is 'Known Bugs'


 * ? Sometimes there are random cacti on mountains.


 * ? Nether fortresses are not spawning (checked on 2 worlds using MCedit to check every part of the currently generated map for them. More extensive testing may be required.)
 * Make sure your MC Edit is up to date -- May just be generating an older version of Minecraft that doesn't have the Fortresses
 * They do spawn... I found two of them on my world in 350 block radius from my spawn position (Nether portal)


 * undefined Beaches no longer generate.
 * They're not supposed to apparently.

= References =