Video problems in Sierra

After upgrading to Sierra a lot of my .m4v video files won't play anymore. It shows the icon as a white folder with a folded corner on the right side. I am able to play them in VLC player but they will no longer play in iTunes and Plex wont recognize them, showing "There was a problem playing this item". When I click play in iTunes the progress bar says Live and the time isn't moving. Ive tried to reconvert the files but they show up the same. I can move the file to my laptop running El Capitan and they look and play normally in iTunes and Plex.