If you see a 'This movie requires QuickTime' message in iTunes
Content that you buy or rent from the iTunes Store plays in iTunes, but you might need a different media player to view some older files.
You can play a variety of media files, such as those that you buy or rent from the iTunes Store, in iTunes. However, some older files might cause iTunes to display a message that says:
"This movie requires QuickTime, which is not supported by this version of iTunes."
If you see this message, try viewing the files using a different media player.
If you're using macOS
Control-click the content, then choose "Reveal in Finder."
Control-click the file, then choose Open With.
In the menu that appears, choose QuickTime Player or another media player. Learn what to do if QuickTime Player can‘t open a video file.
If you're using Windows
Right-click the content, then choose "Show in Windows Explorer."
Right-click the file, then choose Open With.
In the menu that appears, choose a video player that supports the format of your file.
Contact the vendor for additional information.