iMac 27" 5K Late 2015 screen artefacts on shutdown

kallenemvalts wrote:

Upgraded to 10.12.4 a few days ago. So far no problems. Shutdown behavior is a little different from before: now, it dims the screen background photo for a second, then shuts down cleanly.

Exactly the same for me since updating to 10.12.4. I no longer have the color lines. I do still have the thin vertical lines when I enter Time Machine, but I'm not worried about that.

It would seem that this latest update corrected the problem.🙂 My first two iMacs seemed to have no issues the first couple of weeks and then got progressively worse. I will remain cautiously optimistic for a few weeks for that reason. It would be nice if Apple puts this issue to rest once and for all. I have been watching this forum for some time and so far the general consensus follows the same line as your post. This is good news, or at least I want to see it as good news.

Thanks for posting your outcome.

I've not had it yet since the update (ha ha will now though I've said it!), but I have just had an issue waking from sleep where the screen was black but the computer on - I hit the enter key a few times, nothing, and again when it finally came to life - was almost about to hit the power button. When it came on there was a bit of a graphics glitch too right, not quite bright colours but more the odd horizontal line.

Saying that I do recall sleep/wake issues, quite a bit on Google with these iMacs. But rarely do I have it go to sleep.

I read all your feedback and bought a new iMac 5K late 2015 - FD 2 Tb, M395. Updated to Sierra (clean installation - formatted the hard drive and installed as a clean sheet - not updated), the system boots a little longer, but everything is as before. I shut dow it off several times - I do not observe any artifacts or color lines. Can you have a problem in that you did an update from the old version and not a complete reinstallation of the system?

My first iMac was replaced by Apple. (Thank you Apple). Like the first on after a dew weeks it also began to have the line issue described in this forum. Reformatting the car drive and reinstalling the OS worked for a short time but with in a month the issue seem to come back. I recently installed mass Sierra Version 10.12.4 and had no issues installing it (I started the install and walked away for a while) Since this installation I have had no issues. But I must also say that while I remain cautiously optimistic that the issues have beed resolved for us all, I want to reserve my elation for a few weeks just to see if this actually does resolve the issues. If things continue until the end of March I will be the first in line to say "thank you Apple" despite it taking two years to figure to out. Being glad the iMac Retina 5k late 2015 build owners may have this long over due correction lets see what happens over the course of the next few weeks. I am glad your system functions well and do hope that it continues to do so.

And so, I saw artifacts - a small rectangle 3-7 centimeters below the right of the screen when turned off - held for 5 seconds - did not have time to take a picture. 👿😠The update improved the situation, but did not solve it. The defect does not always appear - 1/10 shutdowns. It used to be just slyly as I understood - now the defect has simply been reduced. I hope this does not mean a problem with the video card.

I'm working since 6 days on 10.12.4 and had at least 30 shutdowns...

Every shutdown nice and smooth and ends black..... no artefacts

I suppose the artifacts that have been reported by other members have nothing in common with the original ones that were the reason for this post.

Why can't Apple inform transparently on what they have done with 10.12.4?

In fact of the matter is that they have a direct relationship. I have a new device - I installed the sierra yesterday. With full formatting. And the result - caught that moment. The screen is not all in artifacts, but still they are.

This is the exact same thing I had occurred after install the latest update except mine was in the lower right-hand corner. But I believe is, the VRam is corrupt or not properly flushed when shutting down.

It was in the upper left corner as in the photo, more often in the lower right. The problem is not fixed, I have a new device on my hands and it behaves so when I turn it off. I hope in September-October the new version of the operating system will completely eliminate the defect. Though it would be desirable, that was earlier.

It is my opinion that most of the remnant issue has been resolved. It has only happen to me once since the 10.12.4 mass Sierra update. My iMAC Retina 5K 27-inch late 2015 computer use to have a lot of issues but as I mentioned at the beginning the remnant issue has only happened to me once so far. The screen went dark by a series of black horizontal lines (about 1/2 inch wide) moving parallel down from the top until the entire screen was dark them it shut down normally. It appears to start back up with out issues after that and it only happen the one time so...?. Anyway, I hope this information helps.

CORRECTTED TYPOS FRO,M LAST RESPO\NCE:

It is my opinion that most of the remnant issueS haVE been resolved. It has only happen to me once since the 10.12.4 OS Sierra update. My iMAC Retina 5K 27-inch late 2015 computer use to have a lot of issues but as I mentioned at the beginning the remnant issue has only happened to me once so far. The screen went dark by a series of black horizontal lines (about 1/2 inch wide) moving parallel down from the top OF THE SCREEN until the entire screen was dark them it shut down normally. It appears to BE startING back up with out issues after that and it only happen the one time so...?. Anyway, I hope this information helps.

It is only my opinion that 97% has been corrected. Garage Band still does not work *( it won't update the apple loops) and the "artifact" issue while better does seem to occur once in a while. Yesterday, my screen had a wide black line move from the top of my screen to the bottom when I shut down my iMac. This computer is my second one as Apple replaced my original one. So while the artifact issue is much better I don't feel that it has been completely resolved but as I said this is only my opinion. I hope that helps you.

Me too, but I notice the shutdown glitches (blackout from top downward and a small scrambled rectangle) happen when I click on the "Shut Down" button with the screen cursor, which creates a last-second interaction with the screen buffer. My working theory is that these glitches can be avoided by using the Return key instead of the mouse/tablet to confirm the shutdown. We'll see.

This problem has recently occured on my 2015 CrapBook Pro; on shutdown, I see about 5 columns of dotted green lines in blocks of 3, and slightly slanted too. I have had one critical ssd corruption four months back in which I had to do a full reinstall of sierra. Then, just last week I had a minor corruption after messing with vmware fusion. OSX was running in a crippled state until I did the first aid on my ssd. Now, I don't exactly have any problems with performance, but seeing these green lines on shutdown is pretty **** pathetic for $1.8k machine. This is my first and likely -the last CrApple product I'm gonna buy. Oh how I wish I bought a PC laptop instead... somebody help me 😟