I did it again. Upgraded to QT 7.0.3 from 6.5.2 and to system 10.3.4 to 10.3.9, after several Apple application requiered it to install in my G4. Now Quicktime won't open at all and neither does Itunes 6.0.1. I have trashed preferences in every app and the finder, and getting rid of the itunes library with no results. It seems to be a problem with the application trying to acces the audio core. Are this pieces of software incompatible? Can I go back to 6.5.2 on the G4? I had all kinds of problems with my G5 in the video department when I upgraded to QT 7.0.3 also, but fix the problem spending a big deal of money in Apple application upgrades.