Crash



Crashes are unexpected shut downs of Minecraft. When Minecraft crashes, it typically closes immediately, though it may show an error report marking the location of the exception which caused the crash. A sign of a crash is a "Saving chunks" screen. The most common cause of crashes are mods and preexisting bugs. Attempting to modify the files of Minecraft or individual worlds, even with advanced editors, can also cause crashes. Crashes can also be caused by bugs in the game (e.g.: before the 1.6.5 update, shift-clicking an item into a full chest would crash the game.) Crashes can sometimes cause the corruption of save files if the player is not careful enough. Because of this, it is highly recommended that you regularly keep a copy of your save folder (located in the %appdata%/.minecraft directory on Windows systems), to reduce your losses should a world become corrupted as a result of a crash.

Crashes used to have an error report but that feature has been removed. Yet sometimes an error report can quickly flash right before the game closes. Minecraft occasionally will do this on startup, except it stays there, not allowing you to play the game.

Mods
Crashes can easily occur due to mod conflicts, or buggy mods. If you've installed several mods, try renaming the "bin" directory in the Minecraft folder, then start Minecraft. A new bin folder will be created. Now install each mod you desire one at a time, starting Minecraft and assuring that there is no crashing for each mod. Once the crashing starts occurring again, the last mod installed is likely the problem, or another mod simply does not work with it. Either way, either remove the mod you determined to be causing problems, or repeat the first step, except without installing the problematic mod.

Hardware Problems
Problems with your computer's hardware can also easily cause crashing, or buggy behavior. If this is the case, it's likely you're experiencing problems in other, unrelated games as well. If Minecraft is the only game experiencing issues, then it is unlikely to be a hardware issue.

If you are indeed experiencing crashing or visual corruption in other games as well, the first thing to check is whether your computer's vents are blocked, or clogged with dust (which inevitably occurs over time). Dust or vent/fan blockages can cause a problem known as overheating, which may not be severe enough to cause problems during normal computer use, but during more intensive activities such as gaming, the temperature may spike. If you're using a laptop, make sure any vents on its sides or bottom are neither blocked or filled with dust. For a desktop, check obvious fan locations for blockages, and use a flashlight to peer inside the case. If there is lots of dust, or any internal fans appear to not be spinning, you should either take your computer to a repair shop for a "tune-up" (mention that you suspect there is overheating problems), which you will have to pay for, or read a few tutorials online related to computer cleaning (note that a computer's internal components are highly sensitive to damage from ESD (Electrostatic Discharge, basically a static shock), so it would not be difficult for you to accidentally damage your computer).

If your computer appears to not be suffering from overheating related issues, another cause of game crashing could be damaged components, especially either the RAM, or the video card. If the problem just recently started occurring, and you have not recently installed any major updates or software such as Anti-Virus suites, you may want to take your computer to a shop to have it tested, or you can do it yourself using tools such as "memtest86+", "Furmark", etc (however these tools tend to require a medium to large amount of computer knowledge).

It should be noted that even if your computer meets the basic system requirements of Minecraft, there is a possibility that your hardware might have unique issues, something especially common with laptops and OpenGL (the API used by Minecraft to display the game's visuals). If your laptop makes use of a "video-card" in the Intel GMA (Graphics Media Accelerator) series, which are notorious for experiencing issues with OpenGL.

Software
Though unlikely, unrelated software can conceivably cause crashing in games such as Minecraft. The most likely candidates are User Account Control (Win7), various types of Anti-Malware (i.e Anti-Virus, Anti-Spyware, Firewall, etc) software, which could either consume enough system resources to choke other resource hungry applications, or could cause issues as a result of their "Heuristic" real-time scanning. If you recently installed an application such as AV software, try disabling it. If Minecraft stops crashing, you know the AV program is the perpetrator. You can either remove it (not recommended for security reasons), or configure it to ignore Minecraft's folder and executable. If you're unsure of how to, look up some tutorials using Google.

How to Get a Crash Report
More often then not, Minecraft automatically closes itself after a crash rather then displaying an error report. Here are some methods to find the error report.

Method 1

 * 1) Browse to the folder that contains your minecraft.exe launcher
 * 2) With no files selected (left click on background to deselect), Shift+Right Click anywhere in background of the window, and choose "Open command window here"
 * 3) Copy the following code: java -Xms1G -Xmx1G -cp Minecraft.exe net.minecraft.LauncherFrame
 * 4) Right click in the command window, select Paste and then press enter
 * 5) Login, start Single or Multiplayer and reproduce the crash
 * 6) Once you have obtained the crash report, right click on it, select all and copy, then paste it to the proper mod thread for assistance

Method 2
java -Xms1G -Xmx1G -cp "%APPDATA%\.minecraft\bin\*" -Djava.library.path="%APPDATA%\.minecraft\bin\natives" net.minecraft.client.Minecraft pause
 * 1) Make a new text file, and open it.
 * 2) Save the file with a name that can be easily recognizable and quickly found.
 * 3) Put the following code into the file:
 * 1) Save the file, not as a text document, but using the All Files type as minecraft-report.bat
 * 2) Run the file. This will make the game run in offline mode, but should get you the error report.
 * 3) Once you have obtained the crash report, right click on it, select all and copy, then paste it to the proper mod thread for assistance

Method 3
java -Xms1G -Xmx1G -cp Minecraft.exe net.minecraft.LauncherFrame > log.txt
 * 1) Open notepad and paste this code:
 * 1) Click "save as", name the file minecraft-report.bat
 * 2) Underneath where you put the file name there will be a pull down menu named file type, select the file type as All Files, and click save.
 * 3) Run the bat file that you just created. Try to duplicate the crash.  Upon crashing, an error report will be created, named "log.txt".  Congratulations, you have just created an error report.
 * 4) Open the log.txt file
 * 5) Once you have obtained the crash report, right click on it, select all and copy, then paste it to the proper mod thread for assistance.

Method 1

 * 1) Open mcpatcher.
 * 2) Click "Test Minecraft"
 * 3) Go into a singleplayer world or multiplayer server
 * 4) Commit a bug that crashes the game somehow.
 * 5) You should now get the error.

Method 2

 * 1) Go to Macintosh HD/Applications/Utilities and open Console.app
 * 2) Run minecraft and when it crashes the java log will be added to the console, which you can then select and copy

Linux

 * 1) Open a terminal (xterm, gnome-terminal etc.)
 * 2) Run   and watch the console output. You can select and copy it after making the game crash.

Plantages Crash