Level 1

144 points

Screen flicker like dark window shadows

I have been seeing this issue since I upgraded to Big Sur, which might only be a coincidence. Every so often the Mac seems to freeze and the screen shows dark frames like window shadows at 100% black. They flicker and pulse in strength and while this happens the computer appears frozen. Although sometimes I can tab out to another app or the finder and it stops, sometimes I cannot tab out right away, and sometimes tabbing out does not stop it, and sometimes I can tell that whatever I clicked while the computer looked frozen was actually actioned but not when until the flickering stopped. It might last up to 15 seconds or several minutes. generally shorter. For instance I just had several minutes of this and now it seems fine. I am always running a lot of different apps so it is very hard to say if it relates to one of those or not. I have run apple diagnostic and all was fine.

Hoping someone else has seen this or might have a clue if this is more likely a hardware or software issue.

iMac 27″, macOS 11.3

Posted on May 23, 2021 3:06 AM

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42 replies

mwc1979

Level 1

14 points

Jun 1, 2021 9:12 AM in response to Angus Hume

Yeah, that's it. Nice that you were able to capture it. I haven't seen it on any google searches that I've made for this issue.

To give you more context on my usage:

I generally have open the following programs when its happening (just happened 2 secs ago while in sketch):

Adobe Illustrator

Sketch

Microsoft Word

Spotify

Safari

To me it seems to occur when I'm in one of the more graphically intense programs like sketch or illustrator, and I'm moving a layer around or something. Do you have third party RAM installed?

Angus Hume Author

Level 1

144 points

Jun 1, 2021 10:13 AM in response to mwc1979

I do have owc ram installed. You might be right about it being load rather than a specific app. I’ve yet to find a specific combo or situation where I can cause it deliberately. Next time it happens I going to note the time and check console to see if there is any pattern showing up there. It seems really odd no one else is reporting. Maybe soon we will attract another frustrated victim and find some more parts to this puzzle.

mwc1979

Level 1

14 points

Jun 8, 2021 4:45 PM in response to CJamesRun

Yay, welcome to the weird dark windows shadow pulsating club. I'm beginning to think this is something related to Adobe usage, it appears that's a continuing correlation we're all experiencing. We all seem to have some adobe product on - most likely illustrator from the looks of it.

dmarkes

Level 1

4 points

Jul 20, 2021 5:52 PM in response to CJamesRun

I have the exact same issue with a 2019 Mac Pro with AMD Radeon Pro 580X GPU. Like everyone is saying above, happens mostly with Photoshop/Illustrator usage. I also have 384 GB of Nemix RAM installed, so it would appear it's more software related since it's happening across many different types of machines.

Angus Hume Author

Level 1

144 points

May 24, 2021 6:47 AM in response to AnnieL2

As it is used for work it is difficult to do those sort of trouble shooting steps. My first thought was just to post here to see if the same thing has been reported previously, before I try anything else. I’m not running an additional screen. I never saw the issue until relatively recently. And yes I have a lot of apps going, if I had a main suspect I would say Modo. But it is all to tempting to see patterns where there may be none. I would say it has been more frequent last couple of weeks. I am also seeing a higher frequency of crashes in both Modo and Photoshop in particular, and they are almost always reporting a graphics card error in the console report. I have made a recording as well, maybe I can post that to YouTube and link here.

Angus Hume Author

Level 1

144 points

May 24, 2021 8:58 AM in response to rkaufmann87

Maybe you can go back and read my original post. The issue is intermittent so it might not occur for a couple of hours or more. Yes I can make a new user or start up in safe mode but I might need to run it for some time before I can establish if it does not occur under those conditions. If it does not then I need much more time to determine if it is one of the software packages or something in the user account. So I stick by my comment even if you think that makes me incompetent.

mwc1979

Level 1

14 points

May 24, 2021 9:35 AM in response to Angus Hume

I'm having this exact same issue with my iMac since upgrading to Big Sur as well. No other issues like this prior to updating the new operating system. Flashing and the window shadows darkening. Seems to be happening randomly throughout the day. Exact same issue you're seeing with no real difference aside from my operating system update. Happening over the last month or so.

mwc1979

Level 1

14 points

Jun 8, 2021 4:47 PM in response to AnnieL2

Hi AnnieL2 , Is there any follow-up guidance that you can suggest. It seems like it might have something to do with Adobe program usage, when there is a heavy graphical load or maybe gpu usage? Can you provide a follow up here that might help diagnose this issue a bit more.

Jun 23, 2021 8:31 AM in response to CJamesRun

I did a full re-install macOS Big Sur a few days ago, and for a few days it was fine, and then it was back.

Crashes from the GPU, as well as the window outlines showing.

Is it still happening for others as well? Did anyone find a solution?

bniederm

Level 1

8 points

Jul 20, 2021 2:51 AM in response to evoludo

Same issue here - iMac (Retina 5K, 27 Zoll, 2019), 3,6 GHz 8-Core Intel Core i9, 64 GB 2667 MHz DDR4, Radeon Pro 580X 8 GB

not using Adobe software. mostly using outlook and oneNote - some other apps always running including zoom, MSTeams, Safari, Chrome and Firefox.

all works fine for quite a long time until the effect starts.... then for some while it happens several times within 10 minutes or so. Mostly when changing a window, doing an action like copy and paste etc. - Getting tempted to reboot but mostly don't. Then it suddenly doesn't happen at all for a longer time - even days - until it comes back again. so annoying....

not really sure but something I will watch now more carefully - this time it happened when a video was running. I am often in online-conferences and Webex presentations, doing research via YouTube as well - and then documenting things in parallel of those sessions...... no idea whether it is related - I hope this will be resolved sometime soon

Angus Hume Author

Level 1

144 points

Jul 20, 2021 3:26 AM in response to bniederm

Sorry too hear your issues but also good to see another situation with a different software mix. Now we know a little more, like no Adobe apps. I am still suffering the flickering on a regular basis, and often so intense the system is effectively unusable for up to 30 seconds. Interesting that for the last few days I had been using Octane X render which is pounding the GPU and that did not cause any extra issues or cause the issue to be more frequent. I only once had Octane crash, but had Photoshop and Modo crash a dozen times a day all with the same GPU kernel error in console. I've never seen an issue personally that is so hard to track down a specific cause.

rkaufmann87

Level 10

149,012 points

May 24, 2021 7:34 AM in response to Angus Hume

Those troubleshooting steps take 10-15 minutes tops to complete. If your work for some reason won't allow you to do them, please ask the work admin to do it. Any competent admin should know how.

Angus Hume Author

Level 1

144 points

May 24, 2021 11:32 PM in response to mwc1979

I've got a video of it now as well.

https://youtu.be/9eNTG0pOi9g

Jun 8, 2021 5:33 PM in response to mwc1979

My 2019 iMac has the AMD radeon pro 570X. Are there other gpu that this is affecting?

i am not a huge illustrator user, but PS and InDesign both have optional GPU performance options in preferences.

mwc1979

Level 1

14 points

Jun 8, 2021 8:47 PM in response to CJamesRun

I have a Radeon Pro 575

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Screen flicker like dark window shadows