The specific cause isn't clear, but a variety of graphics-related functions seem to trigger the problems, including switching on the NVIDIA GPU, switching to internal or external displays, and running certain GPU-intensive operations in various applications. Some symptoms of the problem include repeated kernel panics, a screen that suddenly goes black, or the inability to wake from sleep. Since then, several crash reports posted to the discussion show a clear pattern of crashes happening in drivers for the NVIDIA GT330M that shipped in 15' and 17' Arrandale-equipped MacBook Pros with switchable Intel and NVIDIA graphics. Numerous reports of crashes have filled an Apple Support discussion thread that sprung up July 20, the same day Lion became available via the Mac App Store. For now, rolling back to Snow Leopard appears to be the best option. Though Apple wouldn't confirm the issue directly to Ars, support engineers appear to be actively investigating the issue. Problems in the NVIDIA graphics drivers that shipped with OS X 10.7 appear to be at the root of kernel panics and system freezes that leave an affected MacBook Pro with a blank black screen.
Users of last year's MacBook Pro models with NVIDIA GPUs are finding the upgrade to Lion to be far less than perfect.
