Imovie has locked up

Imovie locked up while working on a movie. I waited and then went outside to do some yard work; It was still locked up when I came back; I force quit imovie. When I restarted imovie it was still lockked up wiht a spinning ball and pin wheel. I next ran Yasu to clean cache, etc. and restarted the mac. Restarted, it is still locked. I can not get imovie to do anything. I hope someone has a solution for this.

All software is current version and up to date.

Thanks,

Bob