Firstly disable ALL mods, as they will have to be updated before they can work under 2.2 . If that doesn't help or doesn't apply please try a full clean re-install:
- move any valued save games elsewhere
- "delete local content" in Steam-CK2
- manually delete all files and folders left under Steam/CK2 AND Documents/Paradox/CK2
- re-install game in Steam, run a Steam Verify when done.