Over the past few days, quite a few iMac owners have told us they're experiencing systemwide freezes after watching videos. Likewise, Apple's support forums are full of iMac owners experiencing the same issue.
Although the bug is difficult to reproduce reliably, it's not confined to any one type of video. Flash-based YouTube videos appear as likely to cause the system to lock up as viewing movies from the local hard disk in either QuickTime or iTunes.
During the system freeze users can still move the mouse pointer, but the system doesn't recognize any other form of user input. No error message