2020 iMac Screen Glitch on Shutdown

Hello Guys,

at the end, considering that I bought the computer just a month ago, I opted for sending it to customer care hoping that they will fix the glitch. I think that by a week I will have news about it. I’ll let you know how they’ll fix the problem so might you fix it as well.

This is what I think as well. As mentioned earlier in this thread. My local Apple Service Center has replaced my main board and thus Graphic Card 5700. My screen glitch has disappeared since then. So I assume it is a hardware issue which only becomes visible with Big Sur

I've just spoken with Apple support who are FULLY AWARE of this issue

which is currently being investigated from what I was told. I have also

been told it is a software issue and that a fix for this is likely in

in the next, or the next but one update. That's what I was told, so

I'm just feeding back. Very much worth keeping an eye on I would say.

I can't believe people are actually returning their Macs because of a glitch on shutdown. Even if it were a hardware glitch - which is actually proven it is not because the issue does not appear on Catalina - who cares about the shutdown during the shutdown process? The 27" iMac screen technically consists of two screens which are placed next to each other. I'd bet the glitch is most likely due to a true tone command not sent to both screens during shut down. There is one claim in this thread that the split happend during normal operation, but not proven with screenshots or the like.

So here is a picture of the glitch happening during normal operations. If you are using more than one user you will experience the same issue.

I am happy that I got my iMac repaired (replacement of Logic Board) - since then I have not experienced the issue anymore.

I stand corrected. That in fact is not acceptable. I'd love to test this on my 2020 iMac but I need it for work. Is it revertable when you delete the additional user (e.g. not having to reinstall the entire system)?

on my computer, the same glitch was appearing during turning-off or restart. My scare was just that a brand new computer was going to have your same problem in a couple of months so, I preferred to let the customer assistance doing their job and fix properly my brand new computer

Guys, just to let you know that after I sent the computer to customer assistance the problem appeared again. Btw they told me that their specific diagnosis system didn't find any hardware issue, so, the only thing that they can associate to it is Big Sur bug. They just told me to stay relaxed about it and for sure it will go away with the next updates. Fingers crossed

This issue wasn't addressed in the most recent BigSur update but as I have posted elsewehere, I have been told by Apple support this is a software issue, they are aware of it (now), and it will be addressed in the near future. It's annoying more than anything else and of course, shouldn't happen, but I think we just need to be patient a little longer. By the way, I rolled back to Catalina some time ago, as it annoyed me intensely (annoyed nothing else....) and I cannot get this glitch to replicate under Catalina.

They wouldn't give me any details other than it was most definitely not a hardware fault - well I kind of thought that considering how many of us have the issue and it did seem extrodinary to think there were so many pieces of flawed hardware out there and as you say, like me, this isn't replicated under the previous OS Catalina. It doesn't affect performance or anything as far as I know but for Apple this sort of thing should not happen so I won't be Big Surring again anytime soon until this is sorted.

I know it's not for this thread but I found other annoying issues with BigSur that aren't getting addressed, severe Bluetooth non-responsiveness / lagging for one, but that's not for here!

Hi again... I also believe that it will be ironed out sooner or later. But I am just curious. ..If some software bugs causes this glitch like apple tech guy says so, why it doesn't happen to all who are using same software, big sur? Or apple wants us to believe it is not a hardware issue.

That's a good question. I think its related to the videocard types (the AMD Radeon Pro 5500 and 5700 XT i believe) and possibly there are people who are not worried at all and think it's all fine.

But it's a good question which i was also wondering about.

So the question would be. Is the issue happening on all the machines with these cards and BigSur... or on some of them?

If last, then you would think it's hardware related, and maybe also related to iOS but still also hardware...

And then Apple should explain exactly what's happening instead of keeping us in the dark about this. Sure, they are not anxcious to replace a couple of thousand videocards... but still... it's eerie quit about this issue.

Software bugs don't necessary / always replicate consistently and if it's a coding bug with a particular piece (model) of hardware, replacing the hardware and then finding no issue doesn't necessarily mean the issue has actually been fixed. Many users of course may not even notice it or be bothered with it etc. Now I'm no expert just to put that out there but I also (and I don't think I'm being naive here) don't believe for a second Apple would try to hide or deflect what could potentially be a massive hardware headache for them by lying or misleading us. I'm as certain and confident as I can be this will be resolved in the very near future. Those looking for explanations and transparency from Apple here will be, I think, disappointed as they never do that, but they always deal with these types of issue which is the main thing.

Lets hope so Gus. I also am a big Mac (that sounds familiar!!!) user. And have experience in several cases on hardware flaws etcetera... up to now always have been happy with apple and still. As for their privacy matters which i hope they will even make better and better in the future.

So, we will keep our eyes open =)