Sudden flash of gray in the background In the last few days I've had a sudden flash of gray in the background. I'm on MacOS 10.7.5. I'm not able to provide a screenshot because it only happens for a split second, but here is a more or less accurate mock-up:



It happens on average 1 time per hour, though it's not regular. Sometimes 5 mins pass till the next flash of gray. It covers multi-monitors and it also happens if my external monitor is not connected.

Any ideas?
That is because the Dock process isn’t getting enough resources and/or is crashing.

TheDock process is not just responsible for your Dock, but also Mission Control, Launchpad, Dashboard and the Desktop background.

If this happens most frequently during periods of heavy use, then it is not getting enough resources or its resources are being swapped to disk.

If this happens totally randomly, then there is a deeper issue. Try repairing permissions first in that case and report back if it works.