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iRaynor SK

macrumors 6502
Original poster
Nov 15, 2014
492
91
Banská Bystrica, Slovak Republic
Hello,

I'm experiencing this issue, as shown on this Youtube video:


It happened two times on my iMac

Model is iMac Retina 5K Late 2015 with R9 M395X graphics.

I didn't upgrade RAM (if someone asks) but I'm waiting for 16 GB upgrade kit (iMac 5K certified).

Thanks

EDIT: I'm using macOS Sierra 10.12.1
 
My iMac came with Sierra, I got it before week.
If you owned an older version of OS X previously it should be in the MAS and since the 5k was running El Cap before, you'll not run into issues with that version.
 
I have this same problem in my late 2015 iMac 27 inch. When I shutdown my iMac it shows similar display glitch as shown in video. I am on latest mac OS sierra.
 
I have no issues when I shut down my Late 2015 iMac (also running Sierra), but even if I did it wouldn't overly bother me if all that happened is that you get some screen weirdness before it shuts down - it's hardly a major problem :)
 
I see it off and on since going to Sierra when I shut down. Seems to happen more often if I turn my second monitor off before I power down. I use my iMac daily for video-intensive tasks and there is no issues so I do not believe it's failing hardware but something with the OS.
 
I've seen many threads/reports of this and it seems to be a Sierra issue (known issue) and many people anticipate an OS fix...eventually.

I see it randomly. Not worried.
 
I see it off and on since going to Sierra when I shut down. Seems to happen more often if I turn my second monitor off before I power down. I use my iMac daily for video-intensive tasks and there is no issues so I do not believe it's failing hardware but something with the OS.
I have seen it a few days ago for the first time after installing the Duet Display app to use my iPad as a second display. I set the utility to not automatically run on startup, and I have noticed that it only appeared when Duet was running prior to shutdown. So it appears to be software related, a bug with how monitors are handled I suppose.
 
I've seen many threads/reports of this and it seems to be a Sierra issue (known issue) and many people anticipate an OS fix...eventually.
for me, it helped shaped my decision not to upgrade to Sierra. I'm happy with El cap, seems stable enough at this point.

I'd rather not deal with poorly written drivers.
 
for me, it helped shaped my decision not to upgrade to Sierra. I'm happy with El cap, seems stable enough at this point.

I'd rather not deal with poorly written drivers.

I generally now wait for the .2 or .3 release before I upgrade.
 
This has happened to me maybe 2-3 times on my 27" late 2015 iMac 4.0ghz i7 which arrived last week. Sierra pre-installed. I was unable to reproduce it, and it only happened on Shut Down. But now as my fresh re-install of all my software is getting finished, problem seems to have gone away for now. I noticed after using Diskwarrior, overall smoothness of machine was much better, but I'm not techy enough to know if that's related.
 
This just happened to me last night on my new iMac, as I shut it down. I downloaded the latest Sierra update and then instead of doing a restart, as was required, I just shut it down when I was done and that's when it happened.
[doublepost=1481717901][/doublepost]This happened to me last night on my new iMac as I was shutting down after doing a Sierra update. First time it has happened
 
for me, it helped shaped my decision not to upgrade to Sierra. I'm happy with El cap, seems stable enough at this point.

I'd rather not deal with poorly written drivers.

You're also not going to have the horrible memory leaks in Mail on Sierra. I've just rolled back my partner' iMac to El Capitan for this reason.
 
10.12.3 beta no difference. I'm pretty certain this won't get fixed and that Apple isn't even aware of it. The good news is it is only on shutdown/restart randomly and only on Sierra. Just wish I knew what caused it to begin with.
 
10.12.3 beta no difference. I'm pretty certain this won't get fixed and that Apple isn't even aware of it. The good news is it is only on shutdown/restart randomly and only on Sierra. Just wish I knew what caused it to begin with.

I suspect they are aware, but as it's not causing crashes it's not a high priority.
 
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my imac had graphics issues on sierra as well which happened coming out of sleep

i believe apple is just bad
 
Do you use any external drives? I don't have this issue since I stopped using an external drive, it always happened while leaving an external drive connected for a long time and then ejecting it before turning off the iMac.
 
I had the same issue on my first day with my new iMac (last week).

Installed the most recent BETA of Sierra, and haven't had it come back since.

I also cleared PRAM/SMC.
 
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