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 publishing 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.
entities/*.mca	DEPENDS	Contains all of the world's entities data. Present in maps generated in Minecraft 1.17 and later.
data/map_[#].dat	DEPENDS	Stores map data for craftable maps—remove if you are not using custom map items. Other files in this directory can be discarded.
DIM-1/ and DIM1/	DEPENDS	Contains all the region files for The Nether (DIM-1) and The End (DIM1). This is used with the terrain module.
icon.png	NO	A 64x64 thumbnail of the world at the player's spawn position. Present in maps generated in Minecraft 1.9 and later. Instead, make a 290x246 map.png file.
advancements/	NO	Contains advancement files. Present in maps generated in Minecraft 1.12 and later.
playerdata/ or players/	NO	Contains files which store the individual states of each player.
poi/	NO	Contains the point of interests in the world. Present in maps generated in Minecraft 1.14 and later.
stats/	NO	Contains individual players' statistics.
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.
##MCEDIT.TEMP##/	NO	Generated while a map is being edited in MCEdit.
forcedchunks.dat	NO	Typically present 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.