Error Codes › Duplicate mod

Duplicate mod

COAL-008 · Duplicate mod

Two jars in your mods folder register the same mod ID - usually two versions of one mod, or the same file copied twice. How to find and remove the duplicate.

What it looks like in the log

[main/ERROR]: Found duplicate mods:
	sodium: sodium-fabric-0.5.8.jar, sodium-fabric-0.6.0.jar

What it means

Every mod claims a unique ID, and two files in the mods folder are claiming the same one. The loader will not guess which you meant. In practice this is either an old version you forgot to delete when updating, or the same jar downloaded twice under names like somemod.jar and somemod (1).jar.

How to fix it

Delete the older jar. The error names both files - keep the newer, remove the other.
Sort the mods folder by name and look for near-identical pairs and any (1) suffixes. Dragging in an update without deleting the old jar is the most common way to land here.
Check for a nested copy. A mod shipped inside a modpack plus one you installed manually counts as two.
Never rename a jar to disable it. Renaming to somemod.jar.disabled works; renaming to somemod-old.jar leaves it fully active.