World and tick crashes

Missing registry entries — a mod was removed from an existing world

What the log looks like

missing registry entries
registry remapping
unknown registry key
found a duplicate registry

How to fix it

  1. Put the removed mod back, load the world once, then remove its blocks in game
  2. Forge can force-continue, but every block from that mod is deleted
SeverityBreaks something
CategoryWorld and tick crashes

Check your own log

Related errors

World and tick crashesCreate Contraption Crash: Cannot read field "x" because "mf.axis" is nullUpdate the Create mod (and any Create add-ons) to the latest version newer than 6.0.10, which includes the upsWorld and tick crashesIllegalStateException: Invalid pool element found (minecraft:jigsaw)Back up your world folders before proceeding, especially if you are in the middle of a server version upgrade.World and tick crashesServer thread has not responded — Watchdog shut the server downThe trace printed by the watchdog shows what the tick was busy doingWorld and tick crashesTicking entity / Ticking block entity crashThe Entity Type / Block Entity line names what brokeWorld and tick crashesjava.io.EOFException When Loading NBT or Chunk DataMake a full backup copy of your world folder before attempting any file repairs or deletions.World and tick crashesjava.lang.IllegalStateException: Entity is already tracked!Check the stack trace for `TileEntityMobSpawner` or `MobSpawnerAbstract`; if present, find the custom mob spaw