criticalJava ErrorsAffects: All versions
How to Fix java.lang.LinkageError
Fix LinkageError in Minecraft by removing duplicate mod jars and ensuring only one mod loader is active.
Quick Fix
Remove duplicate mod jars from your mods folder and ensure only one mod loader is active.
Error Message
java.lang.LinkageError: loader constraint violationHow to Fix
1
Check for and remove duplicate mod files
2
Ensure only one mod loader (Forge OR Fabric, not both) is installed
3
Clean the mods folder and re-add mods
4
Reinstall the mod loader from scratch
Common Causes
- Two different class loaders loading the same class
- Duplicate library jars in the classpath
- Mod loader conflict
Diagnostic Steps
- List all files in the mods folder
- Remove duplicates or mods for the wrong loader
- Verify mod loader installation is clean
- Restart
FAQ
Can I run Forge and Fabric at the same time?
No. You must use one mod loader per profile. Use separate launcher profiles for Forge and Fabric.