If you’ve connected an external screen to your Mac or MacBook, you might have noticed something odd happening. When you wake the Mac from sleep, the monitor shows nothing but static – the fuzzy screen you used to get in the old days, when a TV channel wasn’t broadcasting or properly tuned (kids, ask your parents). What causes this and how do you fix it?
Mac screen showing static – what’s the cause?
It’s hard to know precisely what’s going on here, but we can safely assume it’s something to do with the graphics. It appears to be a fairly common problem amongst Mac owners, going back some years. There are many Apple support forum posts discussing the problem and when I raised it on Twitter a couple of weeks ago, several folk replied saying they had the same problem on their MacBook.
Fortunately, this problem seems relatively easy to fix. Or, at least, workaround.
How to stop the static on a Mac monitor
To make the static problem go away, you can simply unplug the monitor cable from your MacBook and plug it back in again. This normally fixes the problem immediately.
If you don’t want to keep inserting and re-inserting the display cable, you can toggle the inputs on your external monitor. For example, use the monitor’s controls to select a DisplayPort input instead of the HDMI your Mac is connected to, or vice versa. This should again solve the problem without having to remove any cables.
If you’ve read the Apple support forum post linked above, there are several other – more technical – suggested solutions to the problem, which might deliver a more long-term fix. These include resetting the Mac’s System Management Controller or resetting the NVRAM. However, both of these fixes only apply to older Intel-based Macs, and I’m seeing this problem on a more modern M1 Mac.
If you’ve come across any long-term solution to this problem, do let us know on comments below and I’ll be happy to share.