FAQ

• What does Minecraft Region-Fixer do? It scans Minecraft worlds (Anvil format) searching for errors and reports them. It can also help to fix some of those errors.

• Does it fix worlds unredable by vanilla Minecraft because a mod inserted strange blocks, entities, etc? No. In general Region-Fixer is mostly dedicated to check the integrity of region files, making it independent of of the Minecraft version. So, in general it will work with moded worlds (unless the mod changes the world format or the region format), but it won't remove strange moded things from the world.

• Then what can it fix? It can detect these problems in region files: header problems, chunk header problems, chunk data corrupted problems (typically wrong CRC in compression), wrong located chunks and it can check if a chunk has an unusual amount of entities (zombies, spiders, primed TNT, etc...), this happens sometimes and makes the server to take 100% CPU and hang.

• Can it fix these problems? Well, yes, more or less... If the data of a chunk is corrupted then this chunk is lost. Region-Fixer can use a backup of the map to replace it or just delete it. Although deleting it sounds drastic, you won't notice. Minecraft will regenerate that chunk when needed and the map will look seamless (well, if there was anything built in there then you will notice...). Wrong located and sharing offset chunks can be fixed in the same way, replacing it using back-up or by deleting them. And with entities, Region-Fixer can remove all the entities in a chunk that has too many of them.