Late 2015 iMac 5k 27" issues

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Late 2015 iMac 5k 27" issues

I just bought a new iMac a few months ago and I'm starting to notice a few issues. The first was the computer was slow to wake from overnight sleep. During the day, if I was away for a few hours, It would wake up within a few seconds. Overnight was a different story. I would tap a key or move the mouse and it would take up to 50 seconds to wake up. A call to AppleCare had me reinstall OS X Sierra without any improvement. The next day and another call had me shut down and unplug the power cord at the back. That didn't seem to help either. On my next call, they had me shut down the computer and do at the reset NVRAM...... hold 4 keys ( P R control & option? ) until I heard two chimes and saw the Apple logo. That seemed to fix it.

Today, I restarted the computer and noticed something very strange on the display. It looked like blue, black and purple lines just before completely shutting down and stayed on the screen for a few seconds. It did it twice in a row on restarts and I was able to take a photo.

Hope someone has some advice as I have no idea what might be wrong and if this computer needs to be taken to my local Apple store. Thanks!

iMac with Retina 5K display, macOS Sierra (10.12), null

Posted on Oct 21, 2016 1:57 PM

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Answer 1

Feb 2, 2017 12:57 PM in response to tjk6277

I also have this issue when I restart. I just brought it to the genius bar (local apple store) and they said they got an email from apple saying it was a known issue after the iOS Sierra release and it was a cosmetic issue(whatever that means??). They said a future update should fix it but I don't know. Does your still act up after motherboard replace? I have a 5K, SSD with 16 GB of ram.

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Answer 2

tjk6277 Author

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Feb 2, 2017 1:11 PM in response to ChristianNOLA

I just got it back from having it serviced again. It was at another repair shop ( not the Apple Store ) under warranty and testing showed no problems. We talked about the issues I'd been having and we decided to try another logic board. So far, it's been perfect. No weird displays on restarts & it wakes right up from sleep. I have no idea if the second logic board fixed the problem or something else happened. The only other change is that I no longer have a USB 2.0 hub plugged into the back of the iMac. I am buying a USB 3.0 hub to replace the old one that I was using. Hope this helps.

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Answer 3

Oct 21, 2016 1:59 PM in response to tjk6277

Since it is still under warranty I would take it in to your local Apple store for proper service and testing.

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Answer 4

tjk6277 Author

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20 points

Oct 22, 2016 2:12 PM in response to tjk6277

I came home from work today & it wouldn't wake up. I had to hold the power button to turn it on. I think it's going to the Apple store for a look. I hope they can figure it out.

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Answer 5

Oct 26, 2016 11:23 PM in response to tjk6277

Please post when you get it fixed.

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Answer 6

tjk6277 Author

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20 points

Nov 6, 2016 4:25 AM in response to growler62000

UPDATE.......

I took the machine to the Apple Store and the tech tested the unit while I was there and everything checked out okay.

I showed him the pictures and video of the iMac when it was acting up. He said they'd like to keep it for further testing and I told him that I upgraded the ram as soon as I got it from 8gb to 32gb. He said he wanted to do some more thorough testing for a couple days and thought that the ram might also be the problem. I got a call after three days and was told the testing showed no problems. The tech gave me the option of having the logic board replaced due to it sometimes causing issues like I've been having. I gave them the go ahead. After a couple more days, I got it back.

I restored it from a Time Machine backup and that was a pain, due to the backup being a newer os version than the version the machine currently had on it. I had to set it up as new, with a new user and then updated to os Sierra. I then used Migration Assistant to move settings, files, etc.

So far, so good. It wakes immediately, seems lighting fast and looks great!!!

Sorry to be long winded, hope this helps.

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Answer 7

Nov 10, 2016 3:41 AM in response to tjk6277

I hope your new iMac is still working perfectly for you.

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Answer 8

tjk6277 Author

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Dec 12, 2016 2:34 PM in response to growler62000

They also said "third party applications" could cause these issues too

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