How to Install UniMixins Without Breaking Your Other Mixin Loaders

Understand the Module System First

UniMixins is not a single monolithic loader. It ships as a set of separate feature modules plus a convenience combined jar. The key advantage is that you can pick only the modules you need, which means you can run it alongside another mixin loader as long as the two do not provide the same feature.

Choosing Between the Combined Jar and Individual Modules

If you are starting fresh and have no other mixin loader installed, drop the combined jar into your mods folder. It bundles every module and just works.

If you already use another loader, do not install the combined jar. Instead, install only the individual UniMixins modules that provide features your existing loader lacks. Check what your current loader already handles (mixin application, compatibility patches, late mixins, etc.) and add only the missing pieces from UniMixins.

Avoiding Conflicts

Two loaders cannot both provide the same feature at once. If you see a crash mentioning duplicate mixin services or a loader refusing to start, you have overlap. Remove either the conflicting UniMixins module or the equivalent feature from your other loader. Because UniMixins is modular, this is usually a matter of deleting one small jar rather than swapping your whole setup.

Verifying It Loaded

Launch the game and check the log for UniMixins startup messages. If mixins from your other mods apply correctly and no duplicate-service errors appear, the combination is working.