A number of early adopters of the OS X 10.7 Lion upgrade are running into a fairly severe bug. What happens is that Macs will crash with a black screen, which requires a forced shutdown. Some systems may show kernel panic messages on-screen, but the majority of them just have a black screen. The issue seems to happen specifically when certain graphics events are happening such as manipulating images in applications, or triggering interface elements when graphics events are occurring. In addition, it happens when systems are woken from sleep.
Most systems that appear to be affected are 2010 … Read more