Fixing 'RebornCore Missing' and Dependency Crashes

The most common RebornCore problem is not a bug in the mod itself — it is a missing or wrong version of the library. Here is how to work through it.

Read the Error, Not the Symptom

When the game crashes on launch, the useful information is in the crash report, not the launcher window. Look for lines mentioning a missing class, a missing mod ID, or a dependency requirement. Those lines name the mod that failed and often the RebornCore version range it wanted. Write that down before changing anything.

Match Versions Correctly

RebornCore must match both your Minecraft version and the dependent mod's expectations. A core built for one major Minecraft release will not load mods built for another. If you updated a dependent mod but left an old RebornCore in place, revert one or update the other so they agree. Remove duplicate copies of RebornCore if you somehow have two — only one can load.

Check the Loader

RebornCore is a code library, so it must be loaded by the same mod loader as the mods using it. Mixing loaders, or placing the file in the wrong folder, produces the same "missing" error even though the file exists. Confirm the file sits in the correct mods directory for your loader and that it is not disabled.

When It Still Fails

If a single dependent mod keeps crashing while others work, the problem is usually that mod, not the core. Test with only RebornCore and that one mod enabled to isolate it.