iMac 2017 27" display issues

[zevrix]

I wonder if anyone ever had this kind of display issues on iMac? (Please see attached pics).

Details:

iMac 2017 27" i7 40 GB RAM
Bought late 2017.

The problem started after a year of use but it was pretty rare - a brief weirdness once in couple of months. (And since the iMac was already out of warranty anyway, I never contacted Apple).

The artifacts disappeared by themselves, or after refreshing the screen by switching apps or a doing a screenshot.

But recently it became a real nuisance. It can happen multiple times an hour sometimes affecting the entire screen, sometimes a single window. Especially when using Xcode but not exclusively.

The effects don't appear on screenshots so I had to take pictures of the Mac.

I did reset PRAM, which didn't make any difference.

I know I need to bring it to Apple for diagnostics for the exact answer. Still wonder if anyone ever had the same problems.

Thanks,
Leo

 

[wilberforce]

I noticed this recent thread with a similar-looking issue (but no solution):

iMac (Retina 5K, 27-inch, 2019) Screen fills with boxes and freezes

Anyone ever seen anything like this? These boxes pop up on the screen and the computer freezes. Tapping keyboard can bring things back to "normal" but it comes back randomly. I thought it might be related to a specific piece of software (Capture One) but seems to happen randomly when other...

forums.macrumors.com

 

[zevrix]

I noticed this recent thread with a similar-looking issue (but no solution):

iMac (Retina 5K, 27-inch, 2019) Screen fills with boxes and freezes

Anyone ever seen anything like this? These boxes pop up on the screen and the computer freezes. Tapping keyboard can bring things back to "normal" but it comes back randomly. I thought it might be related to a specific piece of software (Capture One) but seems to happen randomly when other...

forums.macrumors.com

thanks - yes, it's exactly the same. funny we posted it only few days apart...

 

[rpmurray]

Just curious, I don't have an explanation, but those boxes on the screen look like windows with missing contents. So do they reflect the state of your open windows, possibly for more than one desktop space, or are they just random?

 

[zevrix]

Just curious, I don't have an explanation, but those boxes on the screen look like windows with missing contents. So do they reflect the state of your open windows, possibly for more than one desktop space, or are they just random?

I don't know. They do look like some kind of window artifacts. Maybe they are somehow related to some or all open windows on the machine possibly shifted to whatever direction but that would be impossible to verify. I don't use spaces.

 

[rpmurray]

I was theorizing that it might be the WindowServer process running amok, and placing the outline of already open windows over everything else you have open. You wouldn't happen to be running any window management software like Moom?

 

[zevrix]

Nope no window management software