WORK-AROUND: .MOV Unreadable Files from iPhone to QuickTime Player & FCPX
This post is an explanation of my work-around, to enable unreadable .mov files from an iPhone, to be viewed/used on either QuickTime Player or Final Cut Pro X.
THE PROBLEM
I could see the downloaded files in my Finder window, but they only showed an .mov icon, not a thumbnail image. I couldn't view it on QuickTime Player, but could view it within the Google Drive file sent to me by the client, as well as on a TLC.app but couldn't export it to do editing.
MY WORK-AROUND SOLUTION
I uploaded the unreadable .mov file onto my Youtube channel (as private/unlisted), which basically converts video to FLASH files. I then downloaded that video from my Youtube channel as an .mp4 file, and presto, I could view it and use it within FCPX. I suppose if you still need the video as an .mov file, you could convert the downloaded .mp4 to .mov, but for me the .mp4 format was fine for the project I was working on.
I'm using a 5 yr old MacBook Pro and FCPX v.10.4.
Don't know if this helps you, but it worked for me when other conversion apps didn't work. Good luck!
MacBook Pro 15″, macOS 10.12