java.lang.RuntimeException: Error running OptiFine patcher at C:\Users\Administrator\Desktop\mc by kzzu\mcdata\mods\OptiFine_1.16.5_HD_U_G6.jar on C:\Users\Administrator\Desktop\mc by kzzu\mcdata\libraries\1.16.5.jar
at me.modmuss50.optifabric.mod.OptifineSetup.runInstaller(OptifineSetup.java:214)
at me.modmuss50.optifabric.mod.OptifineSetup.getRuntime(OptifineSetup.java:108)
at me.modmuss50.optifabric.mod.OptifabricSetup.run(OptifabricSetup.java:46)
at com.chocohead.mm.Plugin$$Lambda$63/815336475.accept(Unknown Source)
at java.util.ArrayList.forEach(Unknown Source)
at com.chocohead.mm.Plugin.getMixins(Plugin.java:340)
at org.spongepowered.asm.mixin.transformer.PluginHandle.getMixins(PluginHandle.java:128)
at org.spongepowered.asm.mixin.transformer.MixinConfig.postInitialise(MixinConfig.java:796)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.prepareConfigs(MixinProcessor.java:568)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.select(MixinProcessor.java:462)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.checkSelect(MixinProcessor.java:438)
at org.spongepowered.asm.mixin.transformer.MixinProcessor.applyMixins(MixinProcessor.java:290)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClass(MixinTransformer.java:234)
at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClassBytes(MixinTransformer.java:202)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.getPostMixinClassByteArray(KnotClassDelegate.java:422)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.tryLoadClass(KnotClassDelegate.java:323)
at net.fabricmc.loader.impl.launch.knot.KnotClassDelegate.loadClass(KnotClassDelegate.java:218)
at net.fabricmc.loader.impl.launch.knot.KnotClassLoader.loadClass(KnotClassLoader.java:112)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Unknown Source)
at net.fabricmc.loader.impl.util.DefaultLanguageAdapter.create(DefaultLanguageAdapter.java:50)
at net.fabricmc.loader.impl.entrypoint.EntrypointStorage$NewEntry.getOrCreate(EntrypointStorage.java:117)
at net.fabricmc.loader.impl.entrypoint.EntrypointContainerImpl.getEntrypoint(EntrypointContainerImpl.java:53)
at net.fabricmc.loader.impl.entrypoint.EntrypointUtils.invoke0(EntrypointUtils.java:47)
at net.fabricmc.loader.impl.entrypoint.EntrypointUtils.invoke(EntrypointUtils.java:35)
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.impl.launch.knot.KnotClient.main(KnotClient.java:23)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at me.modmuss50.optifabric.mod.OptifineSetup.runInstaller(OptifineSetup.java:212)
... 28 more
Caused by: optifine.xdelta.PatchException: truncated source file, aborting
at optifine.xdelta.GDiffPatcher.copy(GDiffPatcher.java:181)
at optifine.xdelta.GDiffPatcher.runPatch(GDiffPatcher.java:130)
at optifine.xdelta.GDiffPatcher.(GDiffPatcher.java:67)
at optifine.xdelta.GDiffPatcher.(GDiffPatcher.java:63)
at optifine.Patcher.applyPatch(Patcher.java:152)
at optifine.Patcher.process(Patcher.java:90)
... 33 more

Redownload Optifine as it appears to be corrupted. Also next time please do a search to see if your issue has already been solved. If this solves your issue please close the ticket.