Did you ever sort out your “Unexpectedly Quit” issue? I’m experiencing the same thing right now. My only suspicion is that the Software Update app interfered with the normal operation of FCP. Software Update flashed onscreen during my session, and although I didn’t update anything, I feel that the sudden competition for my CPU’s resources may have caused the corruption.
I have not been able to restore that project, nor do the Autosaves open (from that day. The autosaves from two days ago function properly). My only suggestion is to make sure that your Update app doesn’t automatically check for updates.