iMac 27" 5K Late 2015 screen artefacts on shutdown

Another day without artefacts! I am cautiously optimistic.

In response to some of the other recent notes here, I didn't notice before but I do see the vertical lines in time machine. I probably never noticed before because I rarely go into the restore. (Screenshotted). Still, this is the longest I've been without the screen artefacts, and I've been careful to reproduce the situations that always set them off before. (Running graphic-intensive programs like MineCraft, and shutting down before closing all programs or unmounting drives in my experience).

As to the clean install/file migration, I've tried it both ways. On my first iMac, which I returned initially due to this issue, I used the migration assistant from and external drive. The issue appeared the minute I installed Sierra, and not before. Then, with this current iMac which is the same in every respect, I did a completely clean install of Sierra from a USB stick and no file migration initially. Before I moved any of my files or programs over (completely clean system) I tried a shutdown, and the problem appeared instantly on the clean system.

Is this definitely a software issue? I've been reading online.

Isn't this a video card issue?

They seemed to have had one back in 2011 and 2012

iMac (27-inch): AMD Radeon 6970M Video Card Replacement Program - Apple Support

I just found this thread today, Jan 13th. So, I'm not sure if it's software or hardware.

I, too, have heard from Apple since posting here.

Apple is very interested in solving this problem.

1) I think it helps to post screen shots of what is happening. Apple can see what's happening on our screens. I did post an image of mine.

2) Posting images will help the Apple systems engineers see similarities and differences.

I could see that the images others were posting were very similar to mine.

3) I also used the link that Etuj posted in this thread on Dec 8, 2016 to report issues to Apple.

http://www.apple.com/feedback/macosx.html

We need to keep posting so Apple has more information.

In the meantime, I'm expecting another 27" iMac, Retina, 3.2 GHz, 1 TB flash drive to be delivered today or tomorrow.

It's helpful to know others are having the same issues.

If it's a software/firmware problem, will Apple notify us that it's been fixed? The Sierra 10.12.3 release notes don't mention it: About the macOS Sierra 10.12.3 Update - Apple Support

I'm still seeing the same glitching on shutdown, but it's intermittent. I'll get several in a row, then several clean shutdowns in a row. I'm sitting on it for now, but once I get close to the end of my warranty period, I may consider taking it in.

Seems like Apple should be motivated to fix it before they get a [boat]load of expensive returns.

Anyone updated to High Sierra who can follow this up if the issue has been resolved?

Anyone installed the High Sierra? Any feedback?

Still no problems so far? 🙂 Hopefully we can update 🙂

Yes, I'm: - Late 2014 -27inch -Core i7 -AMD Radeon R9

I haven't had the issue in a long time. Don't look for a pattern, it's probably a harmless software particularity that happens at random.

Apple ‘geniuses’ however should

• Be aware of the problem [how to be aware ? maybe by reading this forum]
• Stop replacing hardware to solve the problem. To stop a problem you must first of all be able to diagnose it. If you don't know what it is, maybe try a harmless cure like resetting pram, or safe mode & similar -probably won't work, but sounds exciting- medication, but don't cure it by operating.
• <I don't know> is a valid scientific statement, as any genius should know.

TargetCoder,

Very interesting. I had the issue on recently purchased:

• iMac (Retina 5K, 27", Late 2015
• 3.2 GHz Intel Core i5
• AMD Radeon R9 M390

But, does that mean your R9 M395 video card is better (or not defective)?

Techs don't seem to agree. Some say software. Others say it's the video card.

@carol333 ...

Meanwhile, I also think that it's a software problem

Status Quo:

• I did let the i5 check in the store -- with all the stress testing and hardware testing -- no errors
• After I had got it back, and the artefacts did show up -- I replaced the new i5 with a new i5
• The new i5 also showed glitches!
• Now the i7 also showing the weird screen on shutdown - I don't know when I last did a shutdown, but I might have done a macOS update meanwhile

But a fact is: There are no so whatever issues working wit the i5, i7!

So these screen artefacts on shutdown are "only" something making me and apparently other people "nervous" ... rightly

Best,

TC

Apple - best Support ever (thumbs up) 🙂

Just got a call from AppleCare Help Desk to check what's going on and how to fix it.

To speed things up and you get a call as well.

• Make a screenshot of "About this Mac -> Monitor"
• Make a screenshot of "About this Mac -> Overview"
• Make a screenshot of "Monitor -> Color Profile"
• Open Terminal and run "sysdiagnose" --> keep that file for upload

Best,

Same problem here. See first three videos (also see comments): https://www.youtube.com/results?search_query=imac+2015+shutdown+distort

My iMac is at the repair center at the moment but I am starting to think it's due to OS Sierra. Hopefully Apple will sort it out soon. Anyway, if I get it back from the repair center with any news, I'll update here.

I have the same problem too. Bought my 27" iMac on the late of October 2016, OS Sierra. The shutdown issue started on the my first shutdown with my new iMac. From then on it has been occurring every 4/10 times I shutdown my iMac. Have sent back my iMac for repair twice and the problem still persist! Really hope they will come up a solution for this. Very frustrating.

Quick update about what most people already know: My iMac is currently being sent back from the Apple repair center with the message that it is indeed a bug in OS Sierra causing this glitch. No hardware problems. They are fowarding this to whoever is responsible for it. However, let's keep asking Apple to fix it.

Same here.

How many feel a hardware issue or software. I was told VRAM was not flushing cache prior to shutdown (geek friend). To repair the video card in the iMac, from what I am told is a skeletal repair. Had a friend with a total failue to the video card, and they now have flickers every so often all the time. Disheartening for such an expensive desktop.