iMac 27" 5K Late 2015 screen artefacts on shutdown

I have long wanted to buy iMac 5K 2015 (m395), but I was frightened by reports about glitches of the screen when shutting down. I had a iMac 27 late 2012 (GTX675MX), which after 3 years of operation began to issue artifacts first in the browser every 1 month and at Adobe Premiere Pro, Adobe Photoshop and Lightroom. Eventually, he burned a video chip. I really hope for positive feedback that the defect was software and it was fixed. Test actively, it is important for me - I want to buy iMac.

Thank you sooo much helping and so quickly updating to 10.12.4 ! Please, please continue to post your findings with the update. Hopefully 10.12.4 fixes the shutdown artefacts nightmare. I'm crossing my fingers for you/us. Like so many others who have posted on this problem, I am in desperate need of a fix. I'm on my second new iMac with no resolution of the problem.

Here's the background:

I have been an iMac user since the year 2011. However, after this experience, I can't say that I will continue to be.

On Mar 15, 2017, at a physical Apple Store, I purchased a new iMac (iMac Retina 5K late 2015 model, 3.2GHz Intel Core i5 with 6MB L3 cashe, 8 GB of 1867MHz DDR3 SDRAM, AMD Radeon R9 M390 with 2GB of GDDR5 memory, 1TB Fusion Drive, OS X 10.12)

Data migration was done by the Apple Store Geniuses via Migration Assistant from my old 2011 iMac to this new iMac. After about the 5 shutdowns the dreaded screen artefacts appeared. On shutdown the screen would go dark grey followed by about 3 seconds of the artefacts, followed by normal black screen shutdown. I made numerous calls to AppleCare seeking resolution. One person, said Apple is aware of the problem and working on a fix. Another said Apple was unaware of the problem. In all cases the AppleCare people, after going through a few things with me (like NVRam Reset, Safe Mode Start-up) told me they did not know what the problem is due to. Most said they felt it was a software or firmware issue. They suggested a clean reinstall of OS X, something that I was not prepared to do and didn't do. I came away very frustrated and disillusioned with the entire AppleCare experience.

Out of sheer frustration and dispair, I returned the new iMac to the Apple Store. They replaced it with another new one with the same exact spec's. Using Migration Assistant, they did the data transfer from what my new iMac to this new replacement iMac. Then, after their data migration, and while at the Apple Store, I started up the new replacement iMac. Upon the second shutdown, it displayed the same exact shutdown artefacts problem. At that point I went a little crazy. So, the store manager brought out a high level Genius to observe the problem and try to figure out what was going wrong.

First, the Genius ran a diagnostic of the graphics board which showed no problems with the graphic board. At that point, he went into the Genius room to consult with his fellow geniuses. He then told me "their" opinion is that the problem is not hardware related; rather, that it is software related and probably caused by something that migrated from my old 2011 iMac - most likely the USER FILE. And, that while the shutdown problem is a nuisance, it won't damage the computer. In order to identify the software problem he said a clean re installation of OS X would need to be done followed by sequential migration of my files (applications, documents, desktop, etc ... but not the USER FILE). He noted that Migration Assistant could not be used again because it would simply migrate the problem back.

At this point, I have not done the OS X reinstall nor the concomitant sequential files migrations. Seeking a solution to the shutdown artefacts problem has already significantly hampered my work flow. At this point, I can't give it anymore time.

I am considering either living with the problem for now or going back to the Apple Store for a full refund and then going out and buying a PC in its place ... but that opens up a whole new "can of worms" which I'm not sure I want, or have the time, to deal with.

Thanks to everyone who is taking their valuable time to work on this problem. I will continue to vigilantly watch for new posts.

I have not seen the artifacts on Time Machine could that possibly something on your desktop that is bleeding through, also have rebooted twice since the 10.12.4 update and have no colored lines or any other artifacts, I am also cautiously optimistic. I have also changed my display from default to scaled, the box to the left of default, not because of the artifacts but because to works better for my old tired eyes

I just checked my late 2013 MacBook Pro, which has had no graphics issues whatsoever since upgrading to Sierra (also running the latest update), and the time machine lines are there as well. I would say that suggests there is no connection between the shutdown glitch and the time machine lines.

I beg your pardon. I speak German and Russian more than English. The best option is to install the operating system from a flash drive with full formatting of the hard drive. Then transfer your personal files from an external hard drive not through the time machine, but manually. Most likely this way you will avoid the transfer of errors to the new system.

I wouldn't waste my time doing clean installs of the OS. When I bought my iMac a few months ago, I did a clean install of everything and migrated files manually without using Migration Assistant. Still got the artifacts, intermittently. And lately the behavior is changing. One time I saw a ghost image of a text headline that had recently been on the screen. Another time the screen background image "drained" to black from the top down. Another time I saw a small scrambled rectangle inside the screen background image. More recently I'm getting a scramble of colored lines immediately on shutdown, much quicker than before. I still suspect it's a software/firmware problem. Haven't tried the latest OS update yet.

This has been an ongoing problem with the 2015 build and I have been following these threads for some time. The updated OS Sierra 10.12.4 is reported to stop this problem. I installed it yesterday 2/28/17 and while I feel it is to early to say the problem is solved, perhaps Apple (after years of complaints) has finally gotten the message the problem is real and is attempting to salvage some of its customer base. I have read that a lot of folks are going back to a PC and I confess I bought one as I needed the stability I perceived Apple products offered. Just as an oh by the way, Apple did eventually exchange my original iMac with the one I am currently using only to have the same some of the same issues as the first one. Time will tell if this new update corrects the artifact issues a lot of us are having.

Still no problems! And I've continued to try everything possible to set it off. I hope everyone on here with the issue does the update, so they can confirm as well.

I know some had the issue disappear for a few weeks at a time, but it had been virtually constant for me before this update. It would give me more confidence if Apple had explicitly mentioned the fix in the update, but at this point I half expect they wouldn't want to admit it existed in the first place. Still, so far so good.

I tried for a while yesterday to get the lines to show up (they didn't) but wanted to give the build a few weeks t mature before I started yelling YAHOO! I have to say this however, so far it does appear to have corrected the issues I was having and installing the update was easy enough with no issues. So, I remain cautiously optimistic.

Yeah... optimism grows :-)

I updated my late 2015 imac today to 10.12.4 and everything is working fine.... no artefacts on the first 5 times I've shut the computer down.

it's a good feeling...

Please go on reporting all of you guys who have done the update!

I'm waiting for your feedback. Do you often have color conflicts before upgrading? And after the update - did they really disappear completely? To me it is important - I bought iMac late 2015 m395 and yet I do not update from El Capitan to Sierra. In Russia it was a very expensive purchase. I'm waiting for your feedback - it's important for me to know what can be updated.

I updated from El Cap to macOS Sierra 10.12.4. The problem with the horizontal colored lines on shutdown, seems resolved, but the vertical lines in Time Maschine, they are still. Also the window animation of Mission Control in comparison with El Capitan is very sluggish.

El cap is running smooth and fast on my maschine (iMac Retina 5K 27", late 2015, AMD Radeon R9 M390) so i went back to OS X 10.11.6

Best from Germany

ok... after an intense day on my imac (updated macOS 10.12.4) with graphic work in Photoshop, Office use, Mails, a programm deinstallation, a new installation of the CAD software with USB stick, several user changes and over 20 shutdowns there was absolutely no artefact problem anymore.

And everything is working super sound with the new 10.12.4..... am really happy :-)

Good luck to all other updaters.... please do also report your experiences.

Yes it does. My conclusion is it is fixed. However, my gut tells me to wait a few weeks to before I celebrate a two year fix and a computer replacement. I made the change from PC to Apple because I had heard such good things about it. But having bought what was touted the "Best Apple computer ever made" I found it so unreliable I had to spend more money on a PC to do the work this iMac was going to do. So while I am very hopeful that this corrects the issues many of us have had (at least if fixes mine) the first few weeks of my original iiMac worked fine then started having issues. The same can be said for the iMac Apple reluctantly replaced it with. A couple of weeks of a good working computer then it went to **** so to speak. So the bottom line for me is Apple doesn't seem to care how much of their customer base goes to or returns to a PC. The techs I spoke with really work at a disadvantage as it seems Apple policy calls many of them managers. Heck you can call ne a brain surgeon but that doesn't mean I have the skills or authority to do the job. So...I do hope you have a lot of success with the new build of the OS but for me my iMac is now just an expensive pool table. By the way if your interested, Guarageband doesn't work either try to update the Apple loops and see what happens. I have had several techs remove reinstall only to tell me they will turn the problem over to Apple engineering. Heck it]s their App and it won't load...so you tell me how is your Apple wormy?

I've read some posts in this thread that sounded like people wouldn't buy an iMac because of this "flaw". I guess there are two sides to look at here.

On one hand, the colored lines are something that occur only during shutdown, only last a few seconds, don't damage anything, and don't interfere with anything. It's probably a safe assumption that Apple will find a solution at some point.

On the other hand, it's not too much to expect a piece of equipment of this value to function flawlessly out of the box.

But .... for example, would you not buy a car with an active recall on it for something that will be fixed at some point anyway, if you really wanted that car? Especially if the recall was for something that really didn't affect the way you would rive the car.