Uploaded a .mov video to iMove in Mac OSx ElCapitan. Video plays with only sound, no video. I can see the video in the Project Window.?

You did not tell us if you are trying to play the video or edit it. Other thigs that will be useful to know when attempting to diagnose or help you:

Which Mac (iMac, MacMini, MacBook/Pro, tower...);

Which version OSX El Capitan.

Which version iMovie.

Source of the video (camcorder, download from somewhere, smartphone, etc.)

How much physical RAM the Mac has.

How much available hard drive space the Mac has.

Telling us why you think "sending to the desktop" should make any difference.

There may be more - at the moment I don't have enough information to make even an educated guess as to the issue.

If playback only, download and install VLC Player (there is a free player available).

http://www.videolan.org/vlc/

I'm not a Mac user...

Do your old video files work ok? If not, what's changed on the Mac, if they do, what's different about the new file? Are there any other programs on the Mac that can / can't play that file?

I have tried removing the playlist with no luck. Tried sending it to the desktop with no luck. Any ideas?