The client starts with sodium but it doesn't start when Iris is enabled
I uninstalled and installed Feather again. It didn't fix the issue. Can anyone help?
Crash report:
A mod crashed on startup!
net.fabricmc.loader.impl.FormattedException: java.lang.RuntimeException: Could not execute entrypoint stage 'preLaunch' due to errors, provided by 'sodium' at 'net.caffeinemc.mods.sodium.fabric.SodiumPreLaunch'!
at net.fabricmc.loader.impl.FormattedException.ofLocalized(FormattedException.java:63)
at net.fabricmc.loader.impl.launch.knot.Knot.init(Knot.java:162)
at net.fabricmc.loader.impl.launch.knot.Knot.launch(Knot.java:68)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:28)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at net.digitalingot.rustextension.ProxiedStart.main(ProxiedStart.java:27)
Caused by: java.lang.RuntimeException: Could not execute entrypoint stage 'preLaunch' due to errors, provided by 'sodium' at 'net.caffeinemc.mods.sodium.fabric.SodiumPreLaunch'!
at net.fabricmc.loader.impl.FabricLoaderImpl.lambda$invokeEntrypoints$2(FabricLoaderImpl.java:403)
at net.fabricmc.loader.impl.util.ExceptionUtil.gatherExceptions(ExceptionUtil.java:33)
at net.fabricmc.loader.impl.FabricLoaderImpl.invokeEntrypoints(FabricLoaderImpl.java:401)
at net.fabricmc.loader.impl.launch.knot.Knot.init(Knot.java:160)
... 5 more
Caused by: net.fabricmc.loader.api.EntrypointException: Exception while loading entries for entrypoint 'preLaunch' provided by 'sodium'
at net.fabricmc.loader.impl.entrypoint.EntrypointContainerImpl.getEntrypoint(EntrypointContainerImpl.java:56)
at net.fabricmc.loader.impl.FabricLoaderImpl.invokeEntrypoints(FabricLoaderImpl.java:399)
... 6 more
Caused by: java.lang.RuntimeException: Mixin transformation of net.caffeinemc.mods.sodium.fabric.SodiumPreLaunch failed
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:427)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.tryLoadClass(KnotClassDelegate.java:323)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.loadClass(KnotClassDelegate.java:218)
at net.fabricmc.loader.impl.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:119)
at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Unknown Source)
at java.base/java.lang.Class.forName(Unknown Source)
at net.fabricmc.loader.impl.util.DefaultLanguageAdapter.create(DefaultLanguageAdapter.java:50)
at net.fabricmc.loader.impl.entrypoint.EntrypointStorage$NewEntry.getOrCreate(EntrypointStorage.java:124)
at net.fabricmc.loader.impl.entrypoint.EntrypointContainerImpl.getEntrypoint(EntrypointContainerImpl.java:53)
... 7 more
Caused by: org.spongepowered.asm.mixin.throwables.MixinApplyError: Mixin [mixins.feather.json:iris.MixinIrisRenderingPipeline from mod feather] from phase [DEFAULT] in config [mixins.feather.json] FAILED during PREPARE
at org.spongepowered.asm.mixin.transformer.MixinProcessor.handleMixinError(MixinProcessor.java:638)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.handleMixinPrepareError(MixinProcessor.java:585)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.prepareConfigs(MixinProcessor.java:570)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.select(MixinProcessor.java:462)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.checkSelect(MixinProcessor.java:438)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.applyMixins(MixinProcessor.java:290)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClass(MixinTransformer.java:234)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClassBytes(MixinTransformer.java:202)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:422)
... 17 more
Caused by: org.spongepowered.asm.mixin.transformer.throwables.InvalidMixinException: The specified mixin 'net.digitalingot.feather.mixin.client.iris.MixinIrisRenderingPipeline' was not found
at org.spongepowered.asm.mixin.transformer.MixinInfo.(MixinInfo.java:864)
at org.spongepowered.asm.mixin.transformer.MixinConfig.prepareMixins(MixinConfig.java:933)
at org.spongepowered.asm.mixin.transformer.MixinConfig.postInitialise(MixinConfig.java:878)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.prepareConfigs(MixinProcessor.java:568)
... 23 more
Caused by: java.lang.ClassNotFoundException: The specified mixin 'net.digitalingot.feather.mixin.client.iris.MixinIrisRenderingPipeline' was not found
at org.spongepowered.asm.mixin.transformer.MixinInfo.loadMixinClass(MixinInfo.java:1318)
at org.spongepowered.asm.mixin.transformer.MixinInfo.(MixinInfo.java:857)
... 26 more

Feather Client is not supported. Please read the list of supported launchers and the installation guide.

Ohhh, thanks! Which launcher do you recommend?

The installation guide you were linked to in my last comment contains some recommendations that support mod developers and are known to work correctly.