by Tom Nelson
I have to say that seeing a Mac’s display suddenly appear distorted, frozen, or simply not turning on is one of the worst problems to come across when all you want to do is work on your Mac. Unlike most other Mac issues, this is one you can’t put off to deal with later.
Having your Mac’s display suddenly start misbehaving can be scary, but before you start wondering how much it will cost to fix, take a moment and remember: many times a display glitch is just that; a glitch, temporary in nature, and not necessarily an indication of continuing troubles to come.
Screen shot © Coyote Moon, Inc.
For example, I’ve seen my iMac display suddenly show a couple of rows of distorted color; not quite a band of distortion, since it didn’t show edge to edge. A few other times I’ve had a window that I was dragging suddenly leave a seemingly permanent trail of smeared images behind as it was dragged about. In both cases, the graphics issues were temporary, and did not return after a restart.
One of the more frightening display problems I’ve run into was when the display never turned on, remaining black, never showing a sign of life. Happily, this turned out not to be a display issue but instead a peripheral that was causing the startup process to freeze before the display was initialized by the system.
My point is, don’t think the worst until you’ve run through these troubleshooting tips.
Before you start the troubleshooting process, you should take a moment to ensure the graphics problem you’re having is indeed a graphics issue, and not one of the many startup issues that manifest themselves as a display that’s stuck in a gray screen or a blue or black screen.
Coyote Moon, Inc. 