27 iMac (2012) crashes and requires smc reset to turn on

I've been heavily using the iMac since late 2013. The shutdowns surfaced only a couple of months ago.

Bought mine very end of 2012. I got about 2 1/2 years out of mine before the shutdowns started this July.

I sent an email to Tim Cook today detailing this problem and the trouble we have all had trying to get it resolved. I read that he sometimes reads emails from customers. I thought it was worth a shot.

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I learned a few more things about this issue that some might want to know.

Looking through this thread, there are quite a few different hardware problems listed. They include logic board and graphic board failures, power supply problems, and a few things that aren't even related to the subject. But the underlying problem with the plurality of users is that some unknown hardware fault that is causing random shutdowns and/or screen anomalies.

There's no "silver bullet" yet, though some have had success with a BGA re-ball - a specialized and pricey procedure. It's not a DIY fix.

The most recent solution for some has been to simply swap out the RAM. Mac RAM can be notoriously finicky. If the computer problem started happening after an update - even if it's from a solid vendor - perfectly functional RAM may have become unstable for some reason. You don't notice this issue much with Apple RAM, but third-party RAM is another issue. (This "fix" isn't relevant if your RAM is soldered in.) If you have old RAM that worked before, you might want to test it out - and post your results here.

After sending in an activity report Apple informed me the problem was isolated to either the RAM or the video card. The RAM is third party (four 8 gig units by Crucial) and I no longer have the original so I'm testing each unit individually to see if I can replicate the issues. Will post the results over the course of the week.

Thank you for testing this out Red, my RAM and video card are original equip so it will be interesting to see if this brings a full resolution. Like the Apple tech said to me at the Genius Bar on my second trip there: "It would be nice to get a win on this issue."

Ok guys,

so I'm now about to join the predicament you are all having!

I have a late iMac (27inch, late 2012)

3.4Ghz i7

32GB (4x 8Gb Crucial) RAM

NVIDIA GeForce GTX 680MX 2048MB

1TB Fusion Drive

OS X El Capitan 10.11.1

Mine has just started today with about 10 shutdowns. This can be after 30mins or within a few seconds of logging into my account.

It's random and not associated with any particular piece of software running. I've unplugged all peripherals which made no difference.

I have to do a SMC reset in order to get the iMac to startup again.

I've already tried a number of solutions inc turning bluetooth off, installing CUDA 7.5.21, using a wired keyboard & mouse but no solution.

I've also ran TechTool Pro 8 from and external Thunderbolt drive and no (hardware) errors are reported.

I've unplugged the RAM and reinstalled it trying one slot at a time, but again it still shut's down.

I've also used DiskWarrior 5 and Onyx, but again no solution.

I bought the iMac in Feb 2013 and I've had no problems with it until today :-(

I suppose my next step is to contact Apple, but I'm non too hopeful after reading the previous 9 pages, but here goes!

Will update you if any solution is found.

I hope you can find the solution.

I am having the same issue as well. I hope apple really take care of this. This obviously is a firmware mistake.

I really think we need to start getting organized. Gather computer details, purchase dates, put all data together and measure how many of us are affected.

I don't know if a Google Spreadsheet is the best approach (I'm concerned about privacy).

I spent 3hrs yesterday with AppleCare staff trying to sort the problem. Their analysis being a software issue.

I reformatted the fusion drive and did an internet recovery install of Mountain Lion in the hope of it ruling out El Capitan. This went well for the next 24hrs with no shutdowns and so I then upgraded to El Capitan tonight.

I re-installed Office,Photoshop etc and all went well. Then I added 3 user accounts and it went bad after the third user account, with the all too familiar shutdown.

I deleted the third account to see if that would isolate the problem but it shutdown again after 5 mins.

I'm now typing after a SMC restart with the iMac running for 10mins now.

Back to Apple(Care) I think tomorrow. This is the weirdest issue I've ever come across :-(.

HI RubenBCN,

Thanks for the suggestions. The Issues happen very often. I have already collected 50 incidents already. I have done PRAM reset, it came out slightly better for 4 days without shutting down. However, after that it is still having the same issue. I will bring the iMac to Genius Bar having a look. I suspect that is power supply issue. May be the capacitors quality is going down.

Regards

Lune

I'm joining in from Norway!

Got mine in April 2013, but not using it on an everyday basis as it is primarily for editing video, which I do sporadically.

I can only estimate crashes to have started 4-5 months ago, when running video editing software. I keep having to re-do work, and it is straightforward embarrassing if a client is present...

Also, the tilt-clutch/spring snapped 2 months ago.

Not impressed... 😟

iMac (27-inch, Late 2012)

3,4 GHz Intel Core i7

16 GB 1600 MHz DDR3 (Crucial)

NVIDIA GeForce GTX 675MX 1024 MB

1TB SATA drive

Update:

The computer has been back from its second visit to the Premium Service Provider for 10 days now and has worked flawlessly since then.

The first time they replaced the logic board (free of charge) and the computer ran issue-free for three days, before the shutdowns re-surfaced. This time they replaced the power unit (again, free of charge). When I came for the second time, the guy that performed the logic board replacement said that my computer was the first one of a series of five to show up with this issue, and that mine was the only one he tried to fix by replacing the LB. The others had the power unit replaced right away.

Unfortunately he was not there when picked up the computer, otherwise I would have asked for specifics like specs of the new power unit or if any of the other computers to get a new one ever came back with the same issue, etc.

My guess is that the issue has indeed something to do with the power unit. A period of 10 days without shutting down was unthinkable since last July, when the problems started.

Fingers crossed!

iMac (27-inch, Late 2012, bought March 2013)

3,4 GHz Intel Core i7

32GB 1600 MHz DDR3

NVIDIA GeForce GTX 675MX 1024 MB

3TB Fusion drive

Add me to the list as well. Have been dealing this for the past 7 months. Brought my 27 inch iMac to the Apple Store only to be told there was nothing wrong with it. They gave me a new power cord. Didn't help at all. Purchased in January of 2013. My specs are as follows:

Definitely keep us posted to see if the power unit seems to be at the root of this issue. It does seem strange that all of these issues began a few months ago for everyone, especially if it's strictly a hardware problem. As an update to my own issue I have now tested each unit of RAM individually and had the shutdowns occur each time. I was advised to take the iMac to the apple store which I will do asap (unfortunately the nearest one is over an hour away).

I will add that I have shared this thread with a couple of Apple reps so they are definitely aware of the issue. The last rep I talked to seemed genuinely concerned so hopefully someone from Apple will get this issue addressed for everyone.