Tutorials/Recover corrupted saved world data

At times Minecraft will hiccup and drop a saved world from the list of those available. The file is still there with the other saved worlds, it's just been corrupted. The missing world, and all your effort there, is recoverable. The things you were wearing and carrying at the time the world got corrupted are not.


 * Access C:\Users\your username\appdata\roaming\.minecraft\saves by going to run and entering %appdata% 

You should see a folder for each of your saved worlds:


 * Make a copy of the corrupted world folder & all files & folders inside, rename it however you please.
 * Start Minecraft and create a new world, then save and close Minecraft.
 * It doesn't matter what the new world is like, you're just going to harvest files from it (the inventory from this world will also be used, so if you want your items back put them into your inventory before closing the game).


 * Go back to .minecraft\saves 
 * There will be a new folder for the world you just created.


 * 'Cut the files (but not'' the folders) from the new saved world folder:
 * level.dat
 * level.dat_old
 * level.dat_mcr (not always present)
 * session.lock
 * And replace the ones in the copy of the corrupted world save file you made earlier.


 * Restart Minecraft
 * You should see a world named whatever you named the new world, but with the corrupted world copy as the seed.


 * Test to make sure the world loads correctly.
 * You will start in a random location and have to find your way back to your settlement.


 * In Minecraft, rename the world "back" to what the original corrupted world was named.
 * Your inventory and eventually some information about mods (f.ex : Thaumcraft research) will be lost.


 * It can be restored with an NBT editor by copying the content of the root node from the file players/yourname.dat to the node "Player" in the file level.dat.


 * It should be almost the same for macs only there is no run or appdata you can get there by opening minecraft and selecting open game Dir. You can also do this in windows but thats the only way you can open it in os x

For Minecraft PE
The instructions above will work on Minecraft PE as well, but the only file you need to copy over is level.dat. The other files don't exist. This was tested on MCPE 0.10.5, but it may work on other versions as well.