I am trying to open a .mov file in "Quicktime" and it keeps saying it doesn't support the file.

I have made a movie in "Final Cut Pro X" saved it as a .mov file and "QuickTime" won't open it. It keeps saying that it doesn't recognize the file. Ironically there is another .mov file right next to it on the flash drive that opens just fine. I do notice that the one it does open looks like a little black box with a 'play' arrow button in it when I run the curser over it, but the one it doesn't open has a 'Quicktime' 'Q' in it.

I try to eject the flash drive and it says "Final Cut Pro X" is still using it, then it shows me a window that shows 6% progress. I am thinking maybe the movie is still loading. I really don't know.