Mod conflicts and mixin errors

Possible causes

• Two mods change the same part of the game's code in incompatible ways.
• A mod is marked as incompatible with another mod.
• Duplicate mods, such as two versions of the same mod in the folder.
• OptiFine installed with Sodium, Iris or other rendering mods.

How to identify the cause

• Mixin errors name the mixin config (for example modid.mixins.json), which tells you which mod failed.
• Check the mods folder for two files of the same mod.
• Remove one of the suspected mods; if the crash disappears, you found the pair.

Step-by-step fix

1. 1Remove duplicate mod files.
2. 2Remove OptiFine if you use Sodium, Iris, Embeddium or similar.
3. 3Update both conflicting mods; conflicts are often fixed in later versions.
4. 4Check both mods' pages and issue trackers for known incompatibilities.
5. 5If no fix exists, keep the mod you need more and replace the other.

If that did not work

• Some performance mods let you disable individual patches in their config, which can resolve a conflict.

Affected versions

All modded versions.

Frequently asked questions