Quicktime 7, when installed on a system with Pro Tools (mine was version 6.4.1) causes a conflict that doesn't allow Qucktime 7 or iTunes to run anymore. Now I'm in trouble because I have to uninstall everything and find a version of Quicktime 6 somewhere so I can fix the problem. I also lost my Quicktime Pro key because of the upgrade. Thanks a lot Apple, I own two macs and I'm a big fan, but what a horrible letdown.