iMac 27" 5K Late 2015 screen artefacts on shutdown

I still cannot see how it can be a video card issue - all was fine in El Capitan, and as soon as Sierra is installed I start seeing these strange graphic issues, on shutdown and in the Time Machine windows. People have rolled back the OS, and bingo, problem gone.

This would be a massive recall if hardware, all those iMacs sold since September 2015 and and being sold currently, all faulty? They would have a lot to answer for if that was the case.

OK, here is some good answers. I have an iMac 27 "Retina 5K 2014 Core i5 and the same problem MacOS Sierra, but not OS X El Capitan. It works perfectly. I believe that the problem is software, not hardware?

Yes it is a model Late 2014 is the same defect. I installed yesterday a "clean" installation of El Capitan and it works perfectly.

I believe strongly that this problem is only due to the Sierra MacOS update, because the problem does not appear in El Capitan

Lot of new posts here today.

My brief comment (posted it before)

NOTE : it really is not just the latest iMac model that has these problems with Sierra....

There are worse - though a bit different 'graphics' problems including 'weird screen artefacts' on the new laptops .. and that is what Apple did try to correct in the latest update 10.12.2

@TargetCoder - Sure hope we didn't jinx you with this discussion!!

You had it for first time today? Oh, no!

And, here I sit, waiting for them to ship me another one.

I'm reading this thread, asking myself if I should cancel the order.

I sure hope it's software, which means it can be rectified.

But, if it's hardware, I'm worried.

Hi carol333,

I have the exact same model as yours, and I have this graphic issues too. In Time Machine there are graphic issues likewise.

I'm back on El Cap and everything is running smooth, without issues – I think, it's a software or driver problem in macOS Sierra.

Best.

it's useless to change iMac with new one.
the artefact is ONLY in OSX Sierra.

if you go back to El Capitan artefact doesn't appear.

I hope next Sierra update solves the problem, otherwise I go back to El Capitan

Thanks to everyone who is responding to this thread.

It's so helpful to hear from others who are experiencing the same thing.

I was so worried it was the video card, but all of your posts have indicated it's software, which means
Apple can address the issue at some point.

Not sure how to go back to El Capitan if I don't have that installer.

Can we download it from Apple site? iMac will come with Sierra installed.

I actually filmed the problem and put a couple of videos on Youtube and then also forwarded this to Apple:

1: https://www.youtube.com/watch?v=8BoCfWj2wFQ

2: https://www.youtube.com/watch?v=mCJJLZVpBB0

3: https://www.youtube.com/watch?v=4G2V9SjPM30

Similar problems have also iMac 27 "Retina 5K (Late 2014). The graphics card is AMD Radeon R9 M290X, 2048 MB, 3.5 GHz processor Intel Core i5 and memory 24 GB 1600 MHz DDR3.

These problems do not have OS X El Capitan 10.11.6. I suspect that it is a software bug?

100% certainty can not be, because Apple has not been confirmed. This is my own assessment and experience of El Capitan.

Does anyone have the same iMac as I do?

@grdh20 - For screen shots, I used a different device.

I used my iPad and captured both video as @Neutie did and took photos.

Or, you can use a camera on a laptop, or stand alone camera and upload the image.

I had the iPad turned on and sitting next to my iMac each time I shut it down.

I was able to capture what the screen was doing.

But, I did have to make sure I had the iPad on and ready to go.

Good afternoon everybody:

I've received this from apple.

Apple is aware of reports of this issue and it is under investigation. We advise you to keep you computer up to date, and there is no need for you to take the iMac to the store.

So, we just have to wait.

Problem still exists in the latest update but by the sounds of it, it looks like Apple have been apprised of the situation and will resolve it in due course.

I was concerned when I wasn't aware that it was widespread and that perhaps it may be due to a hardware failure. But now that I know that's not the case I really don't worry about it much anymore. A bit disconcerting but it doesn't impinge on my experience.

Good Evening

i can confirm that the new update (( doenst work at all ))... after speaking to apple today 24th January 2017 after they replaced my other 27* 5k iMac for one which was built in September 2016 apple are looking into this problem. more people who phone up and speak to apple the quicker the problem will be sorted

(( They are changing all 1tb fusion drives for flash drives for free )) (( jokes))

Regards

Good Evening

i can confirm that the new update (( doenst work at all ))... after speaking to apple today 24th January 2017 after they replaced my other 27* 5k iMac for one which was built in September 2016 apple are looking into this problem. more people who phone up and speak to apple the quicker the problem will be sorted

(( They are changing all 1tb fusion drives for flash drives for free )) (( jokes))

Regards