I'm experiencing a strange phenomenon where most video apps on my Mac — including QuickTime — refuse to open perfectly-good .mov files. These QT movie files are actually output from FCP (probably a mix of 7 and X) and used to open just fine... they're full-res saved exports of completed project timelines, and now that I want to use excerpts from them in a new video, I can't open them at all! Not even the quick-view method of just highlighting their icons and hitting SPACE to preview them.
In a folder containing 64 QT movies, maybe 2/3 of them will not open now. They were created between May, 2016 and March, 2017 so none of them are old enough to blame their age on them not working, especially since I haven't updated my MacOS in that time.
For what it's worth, those that can't open show no useful info in iMediaHUD. Those that I can open (with the quick-view method or in an app) give full info in iMediaHUD.
Any ideas?
— Mike