A block or mob in the world crashes your Minecraft server

Sometimes one thing in the world breaks every time the game updates it: a mob, a dropped item, or a block with data such as a chest, a furnace or a machine from a mod. The server crashes as soon as that part of the world loads, so it crashes again on every start. The crash report names what it is and where. Bring that area back from a backup made before the crash, or remove the thing that breaks.

What you see

• The server stops soon after it starts, or as soon as a player goes to one place.
• A new file appears in crash-reports. Near its top it says Description: Ticking entity (a mob or item) or Description: Ticking block entity (a block).
• The Why your server stopped box on Overview and above the Console says, for example, A minecraft:zombie at 120 64 -340 crashed the server. It names the type and the position when the report gives them, otherwise A mob or item crashed the server. or A block crashed the server. Then: Something about it breaks every time the world updates, so the server crashes again on every start. Restore a backup from before the crash, or remove it with a world editing tool. Its button is Open backups.

Write the position down: the numbers are X, Y and Z.

Bring back only that area

You can put back just the part of the map around that position, as it was in a backup, and keep the rest of the world as it is now.

1. Click Open backups, or Backups in the left menu.
2. Find a backup taken before the crash. Its line says World as of and a time: pick one from before the problem began.
3. Open the menu of that backup (the three dots at the end of its row) and choose Restore some files....
4. Open the tab An area of the map. Choose the Dimension and type the X and Z from the box.
5. Choose The region holding that block, or That region and the 8 around it if the position is close to the edge of a region.
6. Click Restore this area. A running server stops for the moment the files are swapped, then starts again. After a crash your server is stopped, and it stays stopped: when the window says Restored and the area, click Start.

Everything built in that area since the backup is lost, the rest of the world is not touched. You can undo the restore for 24 hours with Undo last restore in the same window. The full guide: How to restore only some files or part of your Minecraft world.

Or restore the whole backup

If the crash came with a change that touched everything, such as a new mod, restore the whole backup instead: in the backup's menu choose Restore to server, then Restore backup. Everything since that backup is lost. See How to back up, restore and reset your Minecraft world.

If the crash comes from a mod

A type with a mod's name before the colon, such as somemod:machine, comes from that mod. Look for an update of the mod first: A mod is made for a different Minecraft version. Removing the mod also removes its blocks and items from the world, so take a backup before you do.

If you have no backup

Remove the broken block or mob with a world editing tool on your computer: download the world, fix it, and upload it again. See How to download your Minecraft world and How to upload your own Minecraft world. If you are not sure, open a ticket with the crash report.

Good to know

• New servers back up every night when the plan includes backups: How to set up automatic backups on your Minecraft server.
• Other causes the panel names: How to see why your Minecraft server stopped.