Cleaning Files

Minecraft will generate quite a few files in your world folder when you create a world. Most of these files are not needed and by deleting them you can reduce the file size when it comes to uploading your world.

Below is a table which displays all the files that may be generated in your world folder, along with a description and whether or not the file is required.

File Name	Required?	Description
level.dat	YES	Stores global information about the world such as name and generation type.
region/*.mca	YES	Contains all the region files of your world. Individual region files using .mcr extension should not be included if the world was converted to Anvil.
data/map_[#].dat	DEPENDS	Stores map data for craftable maps — remove if you are not using custom map items.
level.dat_mcr	NO	A backup of level.dat before the map was converted from the MCRegion world format to Anvil. This is typically seen in older maps built before Minecraft 1.2.1.
level.dat_old	NO	A backup of an older version of the level.dat file.
session.lock	NO	A timestamp when the level was last accessed. This is typically seen while a map is actively being used or modified by a third-party program.
playerdata/ or players/	NO	Contains files which store the individual states of each player.
data/villages.dat	NO	Stores information about Villages in the world.
DIM-1/ and DIM1/	NO	Contains all the region files for The Nether (DIM-1) and The End (DIM1).
stats/	NO	Contains achievements and other statistics.
##MCEDIT.TEMP##/	NO	Generated while a map is being edited in MCEdit.
forcedchunks.dat	NO	Typically seen in maps that was loaded on Minecraft with mods involving chunk loaders.
customnpcs	NO	Generated by MCEdit or NBTEdit.
NEI	NO	Generated by Not Enough Items.
spc	NO	Generated by Single Player Commands.