I'm suddenly getting the message below when I try to open any MP4 video files through File Manager. I tried with Adobe Premiere and Camtasia. It seems the iMac is interpreting all MP4 files as MOV Files and will only open them in QuickTime.
Is it possible you were using a 32 bit version of Camtasia and have now upgraded to Catalina or Big Sur? This is important because all versions of Mac OS from Catalina forward will be using 64 bit apps.
Download the free VLC application and use it. Plays everything.
Hey cmalamed,
Thanks for using Apple Support Communities. We understand that you're having trouble opening MP4 files on your Mac. See if the following steps help: If an audio or video file doesn't play on Mac
If not, have you checked the format of the file is as expected: Get file, folder, and disk information on Mac
If the issue continues, let us know more details:
The more details you can provide the better.
Take care.
I have more details now. Now I get that message when trying to open a file with Camtasia for Mac. For a few years, I had Camtasia associated with MP4 files. Camtasia would be the app I'd use to open video files that needed editing. Now, Camtasia doesn't show up on the list, only Quicktime and Skype do. Not sure where Skype fits in. When I insist on associating Camtasia and opening a file in that way, I get that same strange message above.
Mac suddenly doesn't recognize MP4 files
