I’m sorry you’re still having issues. You’re not the only Mac user who is experiencing this and we’re actively working to solve the problem or at least have a solid workaround. It appears to be a problem with the SketchUp environment when it is upgraded, something is left behind when the upgrade occurs. We will let you know when we have a solution.
We found a temporary solution this past week if you want to try it so you can at least continue to play around with the software. If you create a new user on your Mac and install a fresh copy of SketchUp in that new user’s space, it should work fine. Let me know if you need help doing that.