Last week I made the mistake of opening an old AVI file, which QuickTime automatically converted to m4v. Well it tried anyway; when it got to the end it locked up.

Since then I cannot do any sort of image or movie conversion. QT Player continues to die immediately after launch. Any other program that tries to convert anything also locks up (beach ball). For instance, I just tried to export an image from iPhoto - dead.

I assume that there's a file somewhere that lists which files QT was working on, and it keeps trying to open/convert them (I can see the windows open, then die). Does anyone know where this might be?

  • can you see it in activity monitor
    – Ruskes
    Commented Jul 7, 2014 at 22:02

2 Answers 2


QuickTime in Mavericks saves it's application state to /Users/USERNAME/Library/Containers/com.apple.QuickTimePlayerX/Data/Library/Saved Application State/com.apple.QuickTimePlayerX.savedState/. If you rename that last folder, then QuickTime should then essentially launch with a blank slate.

  • I'll try this tonight. Just in case: where are the converted files stored? I'll want to delete these as well. Commented Jul 9, 2014 at 17:44
  • Tried to find a movie that QuickTime would convert for me to find this out for you but I can't find one. If you can send me a link to one, I'll work it out for you. Commented Jul 9, 2014 at 23:20

Alistair's answer provided the key - when QT attempts a conversion it saves the file to:

~/Library/Containers/com.apple.QuickTimePlayerX/Data/Library/Autosave Information

I could see a file and a plist there. I deleted the file and restarted QT, and presto!

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