Every time I try to open Premiere, I get asked to log in again. When I do that, sometimes I get a message saying premiere failed and other times it opens my project but just asks if I want to save before I close it so I can't do any work! Even if I keep logging in I keep getting the same message -- clearly my login works because I used it to log into this community.
and you might try creating a new user with administrative privileges by going to the mac system preferences: users and groups... if you need any help with this, post back. And not always a smart idea to update your OS in the middle of a project (if you're in the middle of a project). In the future you might consider creating a bootable clone of your startup drive so you can restore your computer to it's previous state after you update the OS. I use Carbon Copy Cloner.