This problem I'm experiencing is so strange! I've just updated to 10.5.7 and I'm still having problems with my cinema display on my new Mac Pro. I've got two screens (1 x 17" Viewsonic & 1 x 20" Cinema display) both connected via DVI. Both displays show bootup screens (grey background & grey apple logo) As soon as I'm into the OS my cinema goes blank. no image. light on (no blinking) but the viewsonic is fine. The cinema isn't detected in system prefs or anything. so far i've swapped DVI > Mini-displayport reset PRAM numerous times tried swapping Connectors on after another tried booting in safe mode Weird thing is, if I boot as windows, montor is still blank, but display prefs actually detects the display and the right resolution! is there anything else I can do? like I said I know the monitor is fine. it works perfectly on my G5 - so it's nothing to do with backlight/power adapter/leads does it just come down to a driver issue damn you any suggestions much appreciated!!