Usually this is as a result of a corrupted project, render or media file.
When this happens, ensure you have a back-up project file in case it becomes terminal – sometimes it can cause a project to become unopenable. Usually, as a precaution, I revert to an autosaved version of the project until the behavior does not re-occur.
You can try replacing or even recapturing the original media in the clip you have a problem with. In my experience, more often it is the render file or (more often) the project file that causes the problem.
ALWAYS use autosave, and if you get a sniff of ‘out of memory’ go back a version or two. Usually I find that is enough to solve the problem. If the project fails to open because of this fault, open FCP by browsing to the autosave folder and clicking on the last autosaved version that works…
Hope that helps.
Ben
Editec Broadcast Editing Ltd
EVS & FCP specialists for live OB operations.
New HD edit/slomo truck on the road this month. Dual FCP systems/6 slomo positions.