I've just upgraded to Lion and my latest problem is that QuickTime will no longer open my .mov files. Everything was fine in my old world. Apart from upgrading to Lion, there's nothing else that's changed.
The document “home-movie.mov” could not be opened. A required codec isn't available.
To see if additional software is available that will enable QuickTime Player to open the movie, click Tell Me More.
I also notice I'm using QuickTime 10.1. I used to have QuickTime Pro - presumably this has disappeared in my upgrade somewhere. It that (a) relevant and (b) a permanent loss? I paid for it - it would be nice to have it back.
Look in the Utilities folder for QuickTime Player 7.6.6.