FCP 7 crashes only when switching to other applications/finder

Question

Hi everyone,
I've been working on a feature film for about 9 months in FCP 7.  All went fine.  I regularly backed up, copied to new projects (have had a few bad experiences with corrupted projects) and have otherwise had no problems.
Last night, all of a sudden, I got the spinning wheel of death while tidying something up.  FCP crashed.  No problem, I restarted it but the same thing happened again.  I trashed my prefs, figure that would fix it but it didn't.  Very strange because I didn't change anything with the project and the file itself is not that big, maybe 35 mb.
After about 20 crahses I figured out that it only crashes when I switch between FCP and another application, say Safari.  I can work away on the project, but as soon as I cmd+tab to any other app (including finder) when I go back to FCP I get the spinning wheel and it eventually shows up as not responding.
I have re-installed FCP 3 times since yesterday, re-installed the OS, repaired the disk permissions, trashed the pref's A LOT, and have now even upgraded the OS to Lion - none of this has had any effect.
If someone sees something obvious that I'm missing please let me know.  I'm tearing my hair out here.  Searching extensively only doesn't seem to yield much.
I'm using a MacPro 1.1, OSX 10.7.4, 2x 3 ghz quad core processors and 14 gb ram.
Thank you for your time
Rick

Answer 1

I've had this problem too and figured out a solution to try before evicerating your system and trial and erroring RAM back into socket.
If you edit anything like I do you like to always be able to go back after making changes so you save all of your old sequences just in case you need to reference them later.  While working on a televison show my FCP projects for each episode consisted of a sequence for each show act and a master sequence of the entire show run, all of which I copied and saved at the end of each day so I could backtrack changes if I needed to.  Multiply this process by two weeks or so and pretty soon my episode projects consisted of at least 28-32 separate sequences in addition to all my media links, music, SFX, etc.
The solution that worked for me was to copy my current project and delete all the old sequences saving only the most recent two copies of my work;keeping a backup copy of my old work but removing them from my active project.
I had to do this folder by folder, about 4 sequences at a time) to prevent FCP from crashing in the middle of the delete but once it was done the problem was solved.  I can switch back and forth between applications without any consequence and I'm back on track and able to work again.  I've since adjusted my workflow so that when I hit four days worth of sequences I duplicate the project and (in the copy) I delete all the past sequences and start from my current cut.  e.g. If I worked for one week and have five folders of past sequences then at the beginning of the next week I copy the whole project, delete the old material and start from my current cut.  If I need to reference old changes I just open up the old project and it's all available without crippling my system.
As best as I can determine the crashes are a result of Final Cut trying to refresh media links to too many things when you toggle back to it from another progam and locking up.  This seemed to solve the problem.
Hope it helps.
~"70% of user error results in software issues 100% of the time"