On a hunch, I opened on my Mac Pro (Leopard) the fcp6 file created on the MacBook Pro (Snow Leopard), saved it with a filename xxxLeopard.fcp, closed fcp, relaunched, and the file plays fine.
So…apparently, at least in my case, a fcp6 file created with Snow Leopard hangs up on Leopard until you save it as a separate Leopard file, close the project, and reopen it.
It doesn’t make a lot of sense, but I’m back up and running on the Mac Pro without the hangups in the timeline.
The Leopard file also plays ok on my MacBook Pro.
Strangely, however, when I open the original file that was hanging in the first place, it now plays fine on the Mac Pro. ??? I don’t have to understand it, as long as it works.
I hope this helps.
Dennis Graves
Mediation Movies Inc