I've tried everything but it keeps giving me this message even tho i have the folder in my mod folder

https://cdn.discordapp.com/attachments/673293236827193352/865208530651054110/unknown.png

I have the same problem. This is the stack-trace:
java.io.UncheckedIOException: Error transforming C:\Users\karst\AppData\Roaming.minecraft.optifine\OptiFine_1.17.1_HD_U_G9_pre29\Optifine-mod.jar
at me.modmuss50.optifabric.util.ZipUtils.transform(ZipUtils.java:108)
at me.modmuss50.optifabric.mod.OptifineSetup.getRuntime(OptifineSetup.java:128)
at me.modmuss50.optifabric.mod.OptifabricSetup.run(OptifabricSetup.java:41)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1511)
at com.chocohead.mm.Plugin.getMixins(Plugin.java:340)
at org.spongepowered.asm.mixin.transformer.PluginHandle.getMixins(PluginHandle.java:128)
at org.spongepowered.asm.mixin.transformer.MixinConfig.postInitialise(MixinConfig.java:667)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.prepareConfigs(MixinProcessor.java:542)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.select(MixinProcessor.java:439)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.checkSelect(MixinProcessor.java:415)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.applyMixins(MixinProcessor.java:285)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClass(MixinTransformer.java:208)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClassBytes(MixinTransformer.java:178)
at org.spongepowered.asm.mixin.transformer.FabricMixinTransformerProxy.transformClassBytes(FabricMixinTransformerProxy.java:23)
at net.fabricmc.loader.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:162)
at net.fabricmc.loader.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:154)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:519)
at java.base/java.lang.Class.forName0(Native Method)
at java.base/java.lang.Class.forName(Class.java:466)
at net.fabricmc.loader.util.DefaultLanguageAdapter.create(DefaultLanguageAdapter.java:50)
at net.fabricmc.loader.EntrypointStorage$NewEntry.lambda$getOrCreate$0(EntrypointStorage.java:106)
at java.base/java.util.HashMap.computeIfAbsent(HashMap.java:1224)
at net.fabricmc.loader.EntrypointStorage$NewEntry.getOrCreate(EntrypointStorage.java:104)
at net.fabricmc.loader.EntrypointStorage.lambda$getEntrypointContainers$1(EntrypointStorage.java:191)
at net.fabricmc.loader.entrypoint.EntrypointContainerImpl.getEntrypoint(EntrypointContainerImpl.java:37)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke0(EntrypointUtils.java:47)
at net.fabricmc.loader.entrypoint.minecraft.hooks.EntrypointUtils.invoke(EntrypointUtils.java:33)
at net.fabricmc.loader.launch.knot.Knot.init(Knot.java:143)
at net.fabricmc.loader.launch.knot.KnotClient.main(KnotClient.java:28)
Caused by: java.util.zip.ZipException: zip END header not found
at java.base/java.util.zip.ZipFile$Source.zerror(ZipFile.java:1587)
at java.base/java.util.zip.ZipFile$Source.findEND(ZipFile.java:1441)
at java.base/java.util.zip.ZipFile$Source.initCEN(ZipFile.java:1450)
at java.base/java.util.zip.ZipFile$Source.(ZipFile.java:1263)
at java.base/java.util.zip.ZipFile$Source.get(ZipFile.java:1225)
at java.base/java.util.zip.ZipFile$CleanableResource.(ZipFile.java:706)
at java.base/java.util.zip.ZipFile.(ZipFile.java:240)
at java.base/java.util.zip.ZipFile.(ZipFile.java:171)
at me.modmuss50.optifabric.util.ZipUtils.transform(ZipUtils.java:135)
at me.modmuss50.optifabric.util.ZipUtils.transform(ZipUtils.java:105)
... 28 more

Try deleting the .optifine folder and relaunching

Thanks! That worked!

i have the folder in my mod folder

What folder in mod folder?

Aside from OptiFabric mod you need to download OptiFine JAR for your Minecraft version from the official OptiFine site and drop it in mods folder too.