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

[elit173]

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 software is running as well.

 

[gilby101]

I see the same occasionally (maybe about once a week) on my 2019 27" 9900K with 580X(8GB). They flicker about for a few seconds and then, if I do something, they disappear. No obvious correlation with what I am doing. Suspect the graphics driver (maybe when the graphics memory is full), but I have no evidence for that. The computer doesn't freeze.

Next time it happens, I will be look a bit harder for a cause. iStat Menus will help with that, then console log.

 

[Nguyen Duc Hieu]

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 software is running as well.

A certain app was triggering all other apps running at once, consuming all the resources and freeze the computer.
You can open Activities monitor to check CPU, RAM usage after the freeze.

 

[zevrix]

I see the same occasionally (maybe about once a week) on my 2019 27" 9900K with 580X(8GB). They flicker about for a few seconds and then, if I do something, they disappear. No obvious correlation with what I am doing. Suspect the graphics driver (maybe when the graphics memory is full), but I have no evidence for that. The computer doesn't freeze.

Next time it happens, I will be look a bit harder for a cause. iStat Menus will help with that, then console log.

I'm having exactly the same issue. Just posted about it:

iMac 2017 27" display issues

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...

forums.macrumors.com

It did start like what you experience: just an occasional occurrence for a few seconds. But recently it became a real constant problem that hinders my work seriously.

I'm taking my Mac for diagnostics soon, but it's most likely a hardware problem. So IF you machine is still under warranty/Apple Care etc. I recommend to nip it in the bud ASAP before it's too late.

Otherwise, you may want to just sell it before this issue overtakes your machine completely (if you can do it guilt-free...)

 

[gilby101]

Does it still happen with macOS 11.5? The update does have some unknown changes (new version numbers) for AMD Radeon kexts.

I'm having exactly the same issue.

Which graphics option in your 2017 27"?

 

[zevrix]

Does it still happen with macOS 11.5? The update does have some unknown changes (new version numbers) for AMD Radeon kexts.


Which graphics option in your 2017 27"?

I'm still on 11.4. I'll keep updated on diagnostic results and if i update to 11.5.

Radeon Pro 575 4 GB

 

[zevrix]

Update:

I brought my iMac to the dealer I bought it from (which is also a full service facility).

I left it there for a weekend to run tests, and they gave me a loaner - a similar iMac 2017.

Guess what: after working on their loaner for couple of days I started experiencing exactly the same display issues. Not so frequent - but the same problem is definitely there.

Also, they just called me to say they could not find any defects with my iMac whatsoever.

Hmmm.

Additional info:

I work off external hard drives. External SSD drive for macOS/apps, and two drives with work projects. Have been working like this for years.

The service guy just told me that running the OS from external hard drive can potentially be an issue and that "Apple doesn't recommend this" - but I think I can discard this opinion. It's pretty common to run macOS off external drives and there's tons of info on this.

So I'm not sure yet what to make out of all this.

They also offered to test my external drives, which I'll do maybe tomorrow.

While I don't believe that working off external drive is an issue, I still wonder if both people on this thread who have the display problem are working off external drives?

 

[frou]

The fact that all the boxes have rounded corners does make it look like more of a software issue, vs. the typical kind of display corruption you see from a broken GPU.

I doubt it's related to the hard drive being external. More like the macOS install is hosed somehow and would benefit from a clean install.

 

[gilby101]

The fact that all the boxes have rounded corners does make it look like more of a software issue, vs. the typical kind of display corruption you see from a broken GPU.

I should have spotted that. Just helps to confirm that this is, most likely, a display driver problem.

I doubt it's related to the hard drive being external.

My iMac boots from internal, so I am sure that blaming it on external booting is a red herring.

I have not seen it on mine since updating to 11.5. But my experience was very occasional, so need at least another week.