Hi, I have had problems and I tried loads of things to do, and I really didn't want to uninstall sims.
But I finally found out the problem!
When you go to type ctrl+shift+c press the windows (windows logo on laptops) before you type it.
E.g : (windows)+ctrl+shift+c
I don't know how that happened,
There's different cures for different people...But this one helped me, so I hope this helps someone else!