How to Fix QuickTime Player Can’t Open MOV/MP4 File You can uninstall the QuickTime Player and then back to the App Store or official download page to install the latest version of QuickTime Player to your Mac. To fix the QuickTime not working on Mac, you can also choose to re-install the QuickTime software. After that, you can try opening QuickTime Player again to check if the problem is solved. Wait for a few seconds and then restart Mac. You can take the regular way to shut down your Mac. When you get the QuickTime Player won’t open issue, you can try restarting your Mac first to solve the problem. In that case, when you run the program, the video playing window won’t appear on the desktop.
Various reasons will cause the QuickTime Player won’t launch problem, such as a corruption in the macOS, or in the files associated with the QuickTime. How to Fix QuickTime Screen Recording Errors
