Trimming Your World (Saving Disk Space)

As your players explore, your world files can grow to massive sizes. But here’s a secret: most of those files are just "chunks" that a player walked through once and never looked at again. Trimming lets you delete that unused data, shrinking your world size and making your backups lightning-fast.

[!IMPORTANT] Safety First: This is a permanent change. Always create a manual Snapshot in Mission Control before you start trimming. [image - Mission Control > Backups | Toolbar | Highlighting the 'Create Snapshot' button for a safety backup before trimming]

Step 1: Get the World onto Your Computer

Since trimming is a heavy process, it’s best done on your own computer using a specialized tool.

Stop your server.
Open the Files tab and download your world folder (and your Nether/End folders if they’re huge). [image - Mission Control > Files | World Folder | Showing the right-click context menu on a world folder with the 'Download' option]

Step 2: Trim with MCASelector

Download MCASelector, as it’s the gold standard for this.

Open the tool and load your world folder.
Find the "Empty" Chunks: Go to Selection > Select Chunks.
The Pro Filter: Use inhabitedTime < 30. This selects every chunk where players have spent less than 30 seconds.
Delete: Click Selection > Delete Chunks. All that "junk" data is now gone, but your players' bases are safe because they've spent hours there!

Step 3: Put it Back

In Mission Control, delete the old, bloated world folder.
Upload your newly trimmed folder.
Start your server.

Pro Tips

Keep Your Spawn: If you have a massive spawn build that nobody "lives" in, make sure you manually un-select it before hitting delete!
Fresh Terrain: A cool side effect of trimming is that deleted chunks will regenerate using the latest Minecraft version. It’s the easiest way to get new biome features into an old world.

Worried about deleting the wrong thing? Join our Discord and we can walk you through the MCASelector settings.