18k errors when extending AnimInstance?

You should see a file in your Source folder, named after your project and ends with “.Target.cs”. Inside you’ll find something like this:


ExtraModuleNames.AddRange( new string] { "YourProjectName" } );

Change it to


ExtraModuleNames.AddRange( new string] { "YourProjectName", "AnimationCore" } );

Rebuild, see if that helps.