how do i fix this?

[thincreator3483]

 

Unable to launch java.lang.RuntimeException: java.lang.ClassNotFoundException: net.minecraftforge.fml.common.Loader at net.minecraftforge.fml.common.launcher.FMLDeobfTweaker.injectIntoClassLoader(FMLDeobfTweaker.java:67) at net.minecraft.launchwrapper.Launch.launch(Launch.java:115) at net.minecraft.launchwrapper.Launch.main(Launch.java:28) Caused by: java.lang.ClassNotFoundException: net.minecraftforge.fml.common.Loader at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:191) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.Class.forName0(Native Method) at java.lang.Class.forName(Class.java:348) at net.minecraftforge.fml.common.launcher.FMLDeobfTweaker.injectIntoClassLoader(FMLDeobfTweaker.java:56) ... 2 more Caused by: org.spongepowered.asm.mixin.transformer.throwables.MixinTransformerError: An unexpected critical error was encountered at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClassBytes(MixinTransformer.java:521) at org.spongepowered.asm.mixin.transformer.Proxy.transform(Proxy.java:72) at net.minecraft.launchwrapper.LaunchClassLoader.runTransformers(LaunchClassLoader.java:279) at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:176) ... 7 more Caused by: java.lang.AbstractMethodError: org.dimdev.vanillafix.ModCompatibilityMixinPlugin.preApply(Ljava/lang/String;Lorg/spongepowered/asm/lib/tree/ClassNode;Ljava/lang/String;Lorg/spongepowered/asm/mixin/extensibility/IMixinInfo;)V at org.spongepowered.asm.mixin.transformer.MixinInfo.preApply(MixinInfo.java:1212) at org.spongepowered.asm.mixin.transformer.MixinTargetContext.preApply(MixinTargetContext.java:1126) at org.spongepowered.asm.mixin.transformer.MixinApplicatorStandard.apply(MixinApplicatorStandard.java:274) at org.spongepowered.asm.mixin.transformer.TargetClassContext.applyMixins(TargetClassContext.java:353) at org.spongepowered.asm.mixin.transformer.MixinTransformer.apply(MixinTransformer.java:724) at org.spongepowered.asm.mixin.transformer.MixinTransformer.applyMixins(MixinTransformer.java:703) at org.spongepowered.asm.mixin.transformer.MixinTransformer.transformClassBytes(MixinTransformer.java:509) ... 10 more

happend trying to launch a 1.12.2 pack i created in overwolf curseforge

[thincreator3483]

i also have this 

A CRITICAL PROBLEM OCCURRED INITIALIZING MINECRAFT - LIKELY YOU HAVE AN INCORRECT VERSION FOR THIS FML

[DaemonUmbra]

1.12 is no longer supported on this forum.

Please update to a modern version of Minecraft to receive support.