I have IMac running on the latest operating systems OSX lion

is it just FCPX that crashes/freezes or the entire computer?

It can be hard to figure out where to post with the new forums. Here is the best place to look.

https://discussions.apple.com/docs/DOC-2463

Here is the Final Cut Pro X forum:

https://discussions.apple.com/community/professional_applications/final_cut_pro_ x

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Look at the console log. Any errors?

Macintosh-HD -> Applications -> Utilities -> Console.app

For problems with bootin' up your system, you should look at console.log. These message are mostly from boot time.

And, for problem with applications, look at system.log. These message are after booting.

Robert