The problem reported here is similar to T96354: Rigify Already Registered as a Subclass (Traceback) Error
But to confirm a report, we need steps to replicate the problem.
From the description I can assume these steps:
- try to install CloudRig from git lab
- try the snow character rig from studio blender
- try to use it on my project
- hit shift+A in armature
- go to preferences to check and uncheck the rigify Addon