QuickTime Player 7 can't play a movie file, what can I do?

Running latest version of El Capitan. Just updated OS X and now my .mov files recorded with a Phantom 3 drone cannot be opened after transferring, getting the following pop-up:

"To see if additional software is available that will enable QuickTime Player to open the movie, click Tell Me More."

Downloaded VLC to try that, but it can't be played from there either, saying the duration is 00:00 even though it's 168.8 MB so I know there's data there. What can I do?