Some users are experiencing an ongoing display issue, primarily affecting Penryn-based MacBook Pros. When the problem manifest, alternating light and dark vertical bands appear on the screen when the system wakes from sleep. The problem is easily fixable on a temporary basis, but it occurs repeatedly for most afflicted users.
As Apple Discussions poster "Atomic Wedgie" writes:
"...every so often, when I wake the MBP (Penryn) from sleep, I see alternating bands of light and dark vertical "stripes" along the screen. It looks as if half the LED backlights did not activate."
The problem appears to be related specifically to Mac OS X graphics drivers as the issue does not manifest when systems are booted into Windows under Boot Camp.
Various reports indicate that Apple Engineers are aware of the problem and are working on a fix -- perhaps to be released in the next Mac OS X update, or with a firmware update for the MacBook Pr. Until then there are several easy fixes for this problem:
- Press control-shift-eject, which forces the display to turn off and reset. This has been the most straightforward fix so far.
- Put the computer to sleep (From the apple menu or close the lid), wait for the computer to sleep, and then open the lid or press a keyboard button to wake it from sleep.
- Restart the computer.