Force QuickTime Player to auto-play files I want QuickTime Player to auto-play a file when I execute that file from Finder.

The default behaviour is to simply load the file and wait for you to press play.

I found a default pref that you can set to force QuickTime X to play movie files automatically.

defaults write com.apple.QuickTimePlayerX MGPlayMovieOnOpen 1


How can you force QuickTime to play all its files automatically, regardless of their type (mp3, wav, aac, etc)
Using the default will command QuickTime to start playback of the loaded file.

defaults write com.apple.QuickTimePlayerX MGPlayMovieOnOpen 1


It's not file specific, or movie specific. It will play all files, regardless of type if you run this command, and restart QuickTime.