Hi Stephen -
You're not alone, although my experience hasn't been as bad as yours, from the sound of it.
My troubles started with X2a:
1. If I close a project, then attempt to open a new one, Sonar crashes.
Work-ardound: Always quit SONAR before attempting to open a second project. God forbid I need two projects open at once (I have found it useful, periodically).
2. Sometimes, when I open a project, Sonar crashes. I usually have to either log out and log in to Windows, or actually reboot the workstation. So far, "coming in clean" usually means I can open the project.
I have no intention of re-installing SONAR - it's much less of a bother for me to follow the work-arounds. Kinda sad, but true.