updated 12:55 pm EDT, Thu July 28, 2011
Video issues linked to QuickTime?
Glitches in OS X Lion are causing freezing for a number of users, according to complaints. The problems are moreover happening under a variety of conditions. For some people, freezes are triggered on waking from sleep. 2011 iMacs appear to be the worst affected in this regard, but some MacBook Pros are suffering the same trouble. Only a reboot temporarily solves the situation.
Some other people are experiencing freezing at Lion's login screen. Disabling automatic graphics switching has been proposed as a solution, but this may not necessarily help. Still others are dealing with occasional freezes when trying to play video, regardless of the app. QuickTime, iMovie, iPhoto, iTunes and GarageBand are all potentially subject, as is a web browser trying to play YouTube videos.
The breadth of the video and graphics issues may mean they are connected to some underlying components in Lion, such as QuickTime. There might also -- or alternately -- be flaws with the current drivers and firmware for graphics chipsets. In either scenario Apple is likely to release updates as soon as it can test fixes to the most critical bugs.