First diagnose: is it really corrupted, or just a structure problem?

When a .mcworld won’t open, in the vast majority of cases the file isn’t actually “broken” — the packaging structure is wrong: level.dat isn’t placed at the root of the archive, or the entire world is wrapped inside an extra folder, so Bedrock can’t find the entry point.

The first step is always to diagnose, not to guess and tinker. Import the file into mcworld.app and run the free on-device diagnostic once; it gives you the type, version, and a health report, telling you whether the problem is at the structure level or a deeper data level (such as the db/ LevelDB database). The diagnostic runs on your device by default, and it’s free.

How to fix: simple repair → advanced repair

Once you’ve figured out what’s going on, handle it according to the severity of the damage:

  1. Import and run the free diagnostic — get the health report and pinpoint which level the problem is at.
  2. Try a simple structure repair — structure problems (level.dat not at the root, an extra wrapping folder) can be fixed for free on your device, producing a new .mcworld that imports normally.
  3. Use advanced repair for deeper damage — for deep damage in db/ chunks or level.dat metadata, use advanced repair to salvage usable data, with an item-by-item change report attached.
  4. Validate and keep the original file — run an import validation on the new file; the original file and its hash are always preserved.

For more complete steps, see the in-depth tutorial Import and Repair Guide.

Product principles and caveats

Repair follows three unchanging principles: it never overwrites the source file — every run produces a new version, and the original file plus its hash are traceable; the diagnostic is free and runs on-device by default; and it doesn’t promise 100% lossless results — if the db/ data itself is already damaged, it can only salvage as much as possible and spell it out clearly in the report. For paid tasks involving advanced repair, failures are refunded automatically, and prices are as shown in the app.

If you want to understand the file itself first, see What is a .mcworld file; if you’re getting an error on import rather than a structure corruption, see What to do when a world won’t open.