Game crashes before the menu
Check the first loader message that names a missing dependency, unsupported Minecraft version or incompatible mod. Do not start by deleting random libraries; the error often tells you exactly which requirement is missing.
“Missing GeckoLib” or dependency error
Install the GeckoLib release that supports your Minecraft version and loader. A Forge GeckoLib file is not interchangeable with Fabric just because the version number looks similar.
Mod does not appear
- Confirm the file is in the active instance’s mods folder.
- Confirm the launcher is actually starting the modded profile.
- Check the loader log for rejected files.
- Make sure you did not download a source-code archive instead of a release jar.
World opens but encounters seem absent
Spawn behavior is intentionally not constant in many Cave Dweller projects. Check configuration, environment rules and whether the build expects specific depth/light conditions before assuming the install failed.
Clean isolation method
- Create a new temporary instance for the same Minecraft version.
- Install only the loader.
- Add required dependencies.
- Add only the Cave Dweller file.
- Launch and test.
- Reintroduce other mods in small groups until the conflict returns.
Keep a copy of working configuration and mod lists. Once the minimal setup works, changes become much easier to diagnose.