I have fabric properly installed, but it shows this when I boot up fabric with ui-utils.
=-Error info-=
Incompatible mod set!
net.fabricmc.loader.impl.FormattedException: Mod resolution encountered an incompatible mod set!
A potential solution has been determined:
- Install fabric, any version.
Unmet dependency listing:
- Mod 'UI Utils' (uiutils) 1.3.1 requires any version of fabric, which is missing!
at net.fabricmc.loader.impl.FormattedException.ofLocalized(FormattedException.java:51)
at net.fabricmc.loader.impl.FabricLoaderImpl.load(FabricLoaderImpl.java:192)
at net.fabricmc.loader.impl.launch.knot.Knot.init(Knot.java:148)
at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:68)
at net.fabricmc.loader.impl.launch.knot.KnotClient.main(KnotClient.java:23)

You also need fabric API

Make sure FabricMC and Fabric API are up to date.