Final Cut Pro X continually crashes

Hi - it's been a while since I was on this forum and I'm really hoping someone out there can help with my issue. Until last night, I had been working away happily with FCPX on my Quad Xeon Mac Pro, when this happened, as far as I remember:

I was coming to the end of a long (and successful) editing session and I came to close down the program. I noticed a warning box which said 'Can't shut down as background tasks are running', or words to that effect. So I left it for a while and then noticed that it had become 'stuck' at about 94% of its task. So I waited a while longer until I was sure that it had hung up, at which time I forced my computer to shut down. When I restarted and tried to load FCPX again, it immediately crashed giving me a large error log message. I vaguely remember that the software update dialogue box was open before I shut down, but I am not sure of this.

OK, I have backups on Time Machine, so I'm not concerned about having lost any work. However, I have tried uninstalling FCPX and reinstalling it, but I still get the same result: the program immediately crashes after it has launched. Do I need to perhaps remove other files as well as uninstalling the main app, do you think? Any ideas, guys?

I occasionally have the problem of FCPX crashing on startup.
Firstly, try starting Compressor first.
If this doesn't work, try trashing the FCPX .plist preferences file. This will mean many of your settings will have to be reset.
Good luck!

I downloader Preference Manager from Digital Rebellion and it did the job perfectly (and for free!). Highly recommended for deleting hidden files - solved my problem!