My video files (mp4, m4v, mov, etc) will no longer play in regular time in QuickTime or Apple TV. The videos play at a super fast speed without any sound for about 10 seconds before it stops, regardless of how long the video is or what file type.
Try booting into safe mode, and try playing videos there. See if it continues:
How to use safe mode on your Mac - Apple Support
To get out of safe mode, restart, and don't press anything on the keyboard.
You can try to install an application called VLC media player, and see if it helps. It's free, so don't worry. It can play audio and video files.
If it still doesn't work, Try to contact apple support?
Try booting into safe mode, and try playing videos there. See if it continues:
How to use safe mode on your Mac - Apple Support
To get out of safe mode, restart, and don't press anything on the keyboard.
You can try to install an application called VLC media player, and see if it helps. It's free, so don't worry. It can play audio and video files.
If it still doesn't work, Try to contact apple support?
Video files no longer play normally in QuickTime
