Some video or audio files won't open

Hello sparkettaccio,

Let's check on the app that is set up to be used with these file formats.

1. Right click on one of these file types > select Get Info.
2. In the window, you should see an option to Open With, select the QuickTime Player app or VLC Player, depending on what you prefer.
3. In this Open With section, you should see the option to Change All, check this to open all similar files with this app.
4. Then try to open that file again and other similar files to see if they open properly now in the correct app.

Resource: Choose an app to open a file on Mac

You may need to complete these steps for each movie or audio file format.

Let us know if this solves the issue for you. If not, are these files on the hard drive of your Mac, in iCloud or another storage service or on an external drive? The more we can understand, the better we can help out.

Take care.

Hi sparkettaccio,

Based on what you've shared media files are not opening as expected. We recommend reviewing the guidance listed in the following support article as it covers resolving this issue on any macOS default app: If a media file doesn't open or play on your Mac, iPhone, or iPad - Apple Support

Should the behavior persist across multiple apps, try booting into safe mode: How to use safe mode on your Mac - Apple Support

Safe mode is particularly useful when you're trying to resolve an issue that doesn't seem to be associated with using any particular app. As always, keeping your software up to date is the first step toward resolving any software issue.

Take care.

Hi sparkettaccio,

Nice work, so far isolating the issue further. At this point, we'd continue isolating this behavior by testing the issue in another user on your Mac. If you already have a second Administrator account, you can switch users and test the issue in the other user. If not, this explains how to create an Administrator account on the Mac: Change Users & Groups settings on Mac Doing this will tell us if the issue may be system wide or more user specific.

Looking forward to hearing your results.

Cheers.

Hi sparkettaccio,

Contacting Apple Support is the best path forward to resolve this issue. They will be best equipped to investigate this further for you:

Get Support

Cheers!