Why duplicate filenames can look unrelated
A mod manager may rename files, append a version, or leave a disabled copy with a changed extension. Manual downloads can also create names ending in (1). The loader reads metadata inside each valid JAR and reports the repeated ID even when the filenames do not match exactly.
Some bundle or connector projects can include another mod internally. Read the duplicate list in the log before deleting files, because the visible standalone JAR may not be the only provider.
Keep the correct copy
Compare Minecraft version, loader and release channel. Keep one build explicitly intended for the current instance and move the other file outside the game directory while testing. Moving it is safer than permanent deletion when you have not yet confirmed the pack's expected version.
Do not combine mods folders from separate game versions. Create a dedicated instance for each loader and Minecraft release so upgrades cannot leave stale JARs behind.
Check what the launcher actually loads
Use the launcher's Open Folder action and verify that you are editing the same game directory named in latest.log. A common mistake is cleaning the global .minecraft folder while a CurseForge, Prism or Modrinth instance uses its own folder.
Launch again after removing one duplicate and analyze the new report. If the duplicate message is gone but another error appears, treat that as a new stage rather than restoring both files.
Quick troubleshooting checklist
- ✓Read the repeated internal mod ID
- ✓Open the active instance folder
- ✓Compare both file versions
- ✓Keep one matching loader build
- ✓Move the extra copy outside the instance
- ✓Analyze the fresh log
Every launch creates a new result. After making one change, use the newly generated latest.log rather than continuing from an older report.