The Quartz on my Mac Pro has started playing up on me today. At first I noticed regular expose was slow and using stacks was slow. I thought nothing of it, thinking it might have had something to do with me burning 2 DVDs at once. It wasn't until the screensaver came on, I normally use Arabesque, but when it came on the black screen with the word "Quartz Composer" came on. (See attachment) I opened up the screensaver settings in the Preferences only to find the only screensavers listed is Flurry and computer name. They work fine. I navigated to the System\Library\Screen Savers\ folder and all the screensavers are still present. I opened the Arabesque.qtz file, only to get the error message "Unsupported Configuration" (See attachment) So then I decided to open System Profiler and check out to see if my card went ratshlt, but everything seems fine there. (Posted screenshot of profiler) Now I'm running a 2008 Mac Pro 8 Core @ 2.8GHz with 10.6.2. The computer came with the 8800GT but I upgraded(?) to the Apple Radeon 4870 card. Does anybody have a clue what is going on here? Can anyone suggest a fix? I wont be able to perform a restart for at least another 5 hours (from this post) as I am downloading.