iMac 27" 5K Late 2015 screen artefacts on shutdown

I, too, have 2nd iMac and it came with the same video card.

It arrived just last week. So, it's newly shipped.

It's doing the same thing the other one did - large bands on shut down, and it did it immediately, right out

of the box.

I did NOT have Office 2016 installed. I purposely did not install things to see if it did it without additional software on the iMac. It did it immediately.

27" iMac, 3.2GHz, i5, 1 TB SSD drive, 8 gigs RAM,

late 2015, 17,1

Just a bit of an update - I have had no issues for a few weeks now, absolutely nothing has changed and I do not use beta updates so I have no idea why it appears to have gone for now. I don't use it everyday, but when I do it is on for long periods, in that it will sleep - the sleeping part seems to be a common theme.

Of course, I spoke too soon and jynxed it. It happened again today again.

Anyhow, Apple called me again and I sent them extensive system diagnostics. It was a good thing it happened just now, because apparently it's easier to pin-point if you can tell them an estimated time when it occurred.

Bought my iMac (Retina 5k, 27", Late 2015. 3.3GHz i5, R9M395, 2TB fusion) in Sept 2016. Immediately updated to Sierra. Noticed artifacts when rebooting or turning off the machine. Took it to a local Apple Store. They did some testing and called me a few days later and told me they couldn't find any problems. They said we could replace the logic board because it sounds like it could be video card related. I told them to go ahead. Got it back a few days later and it was doing the same thing. A month later I decided to take it in again, but instead of the Apple Store, I took it to a local certified repair center that does warranty work. They had it for a week and did some testing and agin no problems found. We decided after a few more days to try another logic board and as of today, I have not had any issues with artifacts on reboot and / or shutdown. The iMac wakes from sleep more immediately now, too. I don't know if an updated logic board might have fixed my problem or something else, but Kudo's to Quadstar Digital Guidance for fixing my iMac. I was considering selling my iMac and going back to a MacBook. Never been so disappointed with Apple......

Don't panic and start swapping hardware. That won't help in the long run. This is an OS level issue that can probably be fixed easily once they figure out what they did to break it in the first place. In addition it seems to be harmless.

I bought it in Kings and already have changed it me 2 times on Monday take him and I train a new one in total have had three iMac and this will be the fourth.

I don't know if it is software or hardware it is to buy an iMac of over €3000 and it should work correctly I hope this works well.

Hi guys, sorry I don't know how to post a message, it looks like there's only the option to answer to one single person.

Anyway, I bought a new iMac in December 2016 and after one week it started showing this problem (I updated the operating system the first day).

I took it back to the Apple Store and got it replaced FOUR times because every time it had the same problem. Apparently no one there knew what the problem was. I wish they informed their staff of what's happening.

I've chatted with a guy at the Apple service and he told me it's a software problem and "they are working on it" and there's no point in me taking back the iMac to the Apple Store.

To be honest the problem hasn't shown itself in the last couple of weeks, actually... different problem this time: now (always when I turn it off) the screen becomes black line by line and slowly.

Since I've replaced it FOUR times in two months then I guess it's not hardware, how could that be?

Thanks.

New problem that you described seems to be so called 'domino effect'. I had similar issue. According to apple support team, it's SW/FW problem. I checked with another apple retailer and according to them, it's HW issue. I didn't wanted to take a chance. So I replaced my iMac (27" late 2015 model)

I'm having this problem too. This is not okay for such an expensive piece of equipment. I bought my iMac in Nov '16 and only started noticing the glitch last month, as I haven't been home to use it much.

iMac (Retina 5K, 27-inch, Late 2015)

Version: 10.12.3 (16D32)

Processor: 3,3 GHz Intel Core i5

Memory: 8 GB 1867 MHz DDR3

Graphics: AMD Radeon R9 M395 2048 MB

Anyone had any luck with returns?

A read through the posts on this topic will show that Apple are definitely looking into this problem.

Several of us have been contacted by Apple and have submitted reports and screenshots.

There is no need to change your iMac.

If this is a software problem, Why does it only seem to be happening on iMacs? Seems there maybe a known problem that Apple aren't letting us know about to avoid yet another secret recall by Apple. They seem to be swapping hardware as a solution.

I had the same issue on my Late 2015 27" 5K iMac that I purchased on November 2016. Since day one the screen would show Matrix green lines, sometimes Blue and Sometimes purple and white lines ONLY when I turn the machine off and NOT every time. I called Apple support and of course they were clueless so I had to carry the machine to the store to be fixed by the Apple 'Geniuses'. They couldn't find anything wrong during their in store diagnostics so they asked me to check it in for more advanced level diagnostics. Called me the second day and told me they can't find anything and asked if I can email them the video of the issue that I took on my phone camera, so I did. They called back in 4 hours and said "It is probably the video card, we're going to have to replace the logic board" I refused to have my brand new computer opened so they replaced my iMac with a similar brand new one. took it home did all the recommended updates out of the box and guess what? Voila! problem is there again on the second brand new iMac which makes me think that it is either a software problem or a hardware issue on a mass number of their late 2015 iMac machines. Does anyone here get the same issue on their iMac that is NOT late 2015 5K 27"?

Wow the posts are certainly coming in now! My iMac was purchased in October 2015 and has this issue, if it were faulty hardware, which I hope isn't, Apple would have one huge recall on their hands! iMacs sold from then right up to present and even now being affected, would be one heck of a recall. Personally, and as I have said before, I believe this is software as only shows in Sierra - here's hoping!

Same problem here. Took delivery of my iMac 27" 5k January this year. First noticed something strange was going on with Logic Pro (unusable atm due to laggy GUI), then started noticing the weird glitches when I power my iMac off.

I have been in contact with support to inform them about the behaviours in case it turns out to be a hardware problem.

My 27" iMac was delivered on Jan 24, 2017. This is my 2nd 27" iMac (returned one bought in Dec 2016)

I did the latest Sierra update two days ago.

It's still getting the wide, colored bands upon shutdown.

The software update did NOT help.
Today is Feb 5, 2017, and I am still getting the strange lines on a brand new iMac.

Apple is trying to work on it. I, too, have been contacted by Apple.