iMac (Retina 5K, 27-inch, Late 2015) Randomly Restarts Without Errors

I have an Retina 5K 27-inch Late 2015 and keeps randomly restart even after all updates in Sierra and before when it had El Capitan too. Samsung 850pro sdd, I have an iMac 27-inch Late 2013 next to this one(5K) same OS, same software, same updates same apps same ssd samsung 850pro NO restarts at all, never!!

Well, I seem to be out of the woods.

Initial replacement of the power supply (was not my idea), followed by the main logic board (yay!) and incidentally the hard drive cable - which got damaged during the previous surgeries.

I got the machine back after 10 days, and the symptoms had worsened - 5 hard power offs (no warning, no freeze) during the first 7 days after I got it back.

So back it went for a third Genius Bar investigation/disassembly over another week, where no fault was found. At that point I was very VERY annoyed, as there was a total refusal to replace the machine under warranty, and all attempts to get a replacement under consumer rights law (as the machine was not of sufficient quality) were refused also.

So I took the machine back and tried to get the Online Store to replace it, as the Retail Store seemingly operate totally separately and can't replace units that were built to order - only the stock builds they sell themselves? Bizarre. Apple is Apple to me. Why is their internal stock control my problem?

So, all was well for 9 more days, then I had another unscheduled hard power off. Having exhausted all avenues to get Apple to take it back, I decided all I could do was a complete "nuke and pave".

So I reformatted the internal drive completely, and installed Sierra as a factory-fresh install. I then *avoided* Migration Assistant and instead recovered my documents *only* by copying from a mounted Time Machine backup. (And then recovering the data for applications that store content in ~/Library/Containers rather than ~/Documents!)

All applications were reinstalled from the App Store / fresh downloads.

So far (touch wood) it's been nearly 4 weeks without another hang / power off. The fact that the machine powered off hard after the MLB replacement makes me believe that actually the largest contribution to stability might be the fresh installation of Sierra. It's possible that something wasn't adequately reconnected after the MLB replacement, was improved in the next visit (thus only one power off) and finally resolved by the Sierra update, but this has been horrific to debug and my heart goes out to the Apple engineers (hardware and software) who have no doubt been working on this behind the scenes.

Apple's reputation for customer service excellence is in tatters for me - because of some appalling communications failures/repeatedly broken promises that made a bad problem worse and basically left me with the impression I was assumed to be lying. Replacing the hardware components under warranty was touted as a "goodwill gesture", but the obstinacy in not replacing the machine which continued to fail after point that seemed arrogant and unreasonable.

Apple refused to release transcripts of my service desk cases to support a complaint in writing / application to the Consumer Rights ombudsman, unless I applied to Apple Legal, which seems designed to impede such course. And they succeeded, because I've lost the energy to do so, regardless of the outcome.

I think this *should* be exposed as a disaster of customer service but frankly would rather put my efforts into something else.

My formal complaint at the end of the process was not followed up and no kind of compensation was offered for the 6 months of phone calls, multiple visits to the Genius Bar etc. Not even an iTunes gift card.

I tell everyone I use Macs because they annoy me less than Windows machines, and stay out of my face. That belief is very severely dented now. I hope Sierra lives up to its marketing, and I can get back to enjoying using my iMac again.

Another one bites the dust.... I have been dealing with Crapple **** for the last two weeks since I got the 10.11.04. update ...and then I thought it may be my work software...a recording program or peripheral.

I narrowed it down to the iMac and called Applecare and they rendered the mac unuseable in two calls trying to reinstall OSX...then dealing with impotent senior advisors who did nothing but send me to a local affiliate.

This is unacceptable for the once reliable computer to find it's imac name becoming a laughing stock.

I had the tech come out and reinstall OSX got it running ...restarts occurred immediately after he left.... now he is taking it into the shop for diagnostics...I told them/him about this thread and the going down to 10.11.03 as well as the Logic board issues, he seems like a great tech and very open so I have hope.

But Apple have to change and fast, that means CUSTOMER RELATIONS! They have lost their way and they lost the big picture... as an entrepreneur and businessman I try to recognize just who is important in the overall equation. Based on this lengthy thread I believe Apple do not.

Cerchiobottista wrote:

So seems I'll get the iMac back with the logic board replaced in a few days: I'll update the thread when I have some news on the situation.

Another chapter of my story as promised.

I got the computer back, with the logic board replaced, on the 24th of November (I sent it for repair on the 7th of November). The package surely took a serious hit during transport, as it was pierced from some kind of impact. Also the handle of the original package was loose: luckily the handle detached when the package was still on the ground, otherwise I would have gifted the Mac with another hit myself.

Anyway I had no kernel panics and / or random reboots since then, so I'm pretty confident that the original problem is solved; although now the display has a yellow tinge / halo running on all four borders of the screen, so it's ready to be repaired again.

On top of that I had the worst experience ever with Apple support (I bought the Apple Care too, by the way).

Just a few random examples:

• The person assigned to my case often didn't bother to answer to my mails: setting up the appointment with the courier and the repair center took almost twenty days.
• I was able to ship the computer almost by chance due to their lack of organization
• During the repair period, from the 7th to the 24th of November, I had no updates at all and at some point I had to "beg" to have some news
• It was shipped back without asking me when I was available to receive the package: just received a mail saying it was on its way
• Today, 12th of December I'm still waiting for an answer after sending, as requested, photos of the display on the 25th of November

I could go on, actually, but you get the gist.

My iMac is almost 10 months old, already spent 24 days in total in repair and I still have to plan another repair for the display.

I have the exact same problem. My 27-inch late 2015 running Sierra began freezing itself followed by a restart a week ago after I bought it in Feb this year. It has now occurred twice in a week and I'm starting to worry about this.

Is there any clear solution to this? I don't wanna read all 21 pages of replies cause it'll be very time consuming if there aren't any(which I suppose).

Hi there - just to add my case: My late 2014 5k iMac started to occasionally go to a black screen and need restarting (as if from sleep) after 15 seconds or so. This became more and more frequent, and installing istat showed me that even a modest load on the CPUs was taking them to 100 degrees centigrade and higher; presumably causing the shutoffs.

I took it to genius bar and they said it needed a new logic board, which they replaced. After testing the 'thermal conductor cable' or something had come loose which caused further diagnostic failures, so they re-sealed that. I now have it home and I'm working with Spotify in the background, two browsers open and Lightroom doing an export (high load over time) and istat tells me all four cores are around 60 degrees centigrade. The fan is not whirring loudly at the moment (1198rpm). Seems like all is good again, but I'll post back here if it goes wrong for me again.

Best wishes,

Nat

Nick, Was this the spotlight index that was bad? So you rebuilt the index and that took care of the issue?

Yes, the Spotlight index

I took Apple to court and won the lawsuit. Apple was ordered to pay me back the money for the product and to pay me half of the value of the product for moral damages.

My current guaranteed crash tool is running Photos, creating a slideshow, using the Origami Theme, adding music and exporting it at 1080p. Never makes it past 50%.

In case anyone else has the same memory I had:

http://www.crucial.com/usa/en/ct8g3s186dm

That is the exact module I swapped out for Kingston HyperX.

-KJ

Did you see my latest updates?

My iMac has > 50 days uptime since I exchanged the RAM with Kingston memory with the same spec as the Crucial sticks which was made for this exact model.

-KJ

Since you replaced your ram with the kingston ones, has the problem come back up since? I have OWC ram installed in mine and am wondering if that's the culprit.