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

My late 2012 iMac, i7 16gig RAM 27 inches keeps shutting down. It looks like as if it was unplugged. Happens randomly. Sometimes while playing Diablo 3, surfing facebook or using iphotos or other apps. Seems to not crash if just left on overnight and not been used.


In order to turn it on again I have to unplug it from the power line for like 30 seconds, only then it starts.


I have the settings set to restart on power failure, but it does not.


Happened a few times a few months back. I have installed a surge protector and it worked fine for like a month or two. However last 2 days it has shut down like 10 times...


Help would be greatly appreciated. I suspect hardware failure.

iMac (27-inch, Late 2012), iOS 7.1.1

Posted on May 5, 2014 9:44 PM

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Posted on Oct 26, 2017 3:46 AM

Hi there - hope I'm on the right thread for this reply.


I recently suffered the same issue for over a week whereby my late 2012, 27" iMac (1TB fusion drive) would unexpectedly shutdown like someone had yanked the power supply cable from the back. I could only get it restarted by removing the power lead for 15 secs, plugging back in and waiting 5 secs before starting up - and apart from a Chrome "unexpected shutdown" message, you wouldn't have known that it had shut off.


I spent a few hours on to Apple Support trying various solutions (Diagnostic test, MemTest, SMC/PRAM resets, Sierra reinstall etc).


By trial and error, I eventually identified the problem's source as being my Satechi 7 port USB 3.0 hub which had 2 x Porsche design (1TG and 4 TB) external HDD's attached, along with 2 x charge/sync docks for iPad and iPhone. Since I removed the USB Hub and plugged the peripherals into the back of the iMac, I have had no issues whatsoever - and my pride & joy is back working like a dream.


I hope this update helps

574 replies

May 6, 2015 9:40 PM in response to sfgswedfstfsd

I hear you 😉 .. It is time for Apple Inc. to own up and rectify the random shutdowns affecting so many - iMac Late 2012 27".

sfgswedfstfsd, I have found that shutting down the imac at night (before bed) and removing the power cord from socket, sometimes allows a full days usage without shutdowns. When inserting the power cord to restart, make sure the power is switched off, insert into imac, switch on, then wait 5 seconds before pressing the computers rear power on button. Run disk repair permissions utility often as well - not sure if this helps, but no harm in doing so.

Also, if upgrading to 10.10.3 use the Combo updater.

GOOD LUCK

May 6, 2015 10:00 PM in response to vanstar sydney

Yes! I've also found that the longer you leave the iMac unplugged, the longer the iMac will stand before the random shutdown. However, the iMac would need to be left alone plugged for a couple of days. I've tried this before and it'll stand for a week or so with no problem.

I swear this $3,000+ machine is designed for anger management... Been using my Macbook Air for almost a year because I'm so tired of it. This couldn't be called a computer if it doesn't even freaking work properly!!! Sigh.. sorry for all the anger.. Been keeping it for a while now.

May 25, 2015 3:52 AM in response to Lagoiski

Hi All, I've also got the same problem. Crash can happen anytime without warning - incredibly annoying. Like mentioned about the restart requires the SMC to be reset. It's really upsetting that I've spent nearly £2,000 on a machine to try and get my freelance off the ground only for all these problems to occur. I can't help but think it's a software compatibility issue with the GPU rather then a hardware fault, as diagnosis tests come back clean and the crashes are so random. Plus the


SPEC:

iMac (27-inch, Late 2012), 3.4 GHz Intel Core i7, 8 GB 1600 MHz DDR3, NVIDIA GeForce GTX 680MX 2048 MB

I've tried all the following things so far with no real luck as yet...


1. Reinstalled OS.

2. Formatted Everything and started over.

3. Installed Cuda driver to cover the GPU errors people are talking about.

4. Installed Java to cover even more errors.

5. Ran Apple diagnostics test - came back clean.


I use Dreamweaver and Illustrator and I've been reading that there are a lot of problems with the GPU and adobe's creative cloud...

May 26, 2015 2:18 PM in response to Lagoiski

I am having the same issue for almost one month now. I opened a case with AppleCare and it has been escalated to AppleCare Engineering. This issue is perplexing because it behaves like a software problem and a hardware problem. Having to reset the SMC obviously points to hardware but it did not act up in a clean partition, which would point to software.


Interestingly, the 27-inch Late 2012 never had an SMC/EFI firmware update but the 21.5-inch Late 2012 did. This may have nothing to do with the issue but I find it very unusual as Apple typically updates firmware on a system at least once within the first year or so from its original release.

May 26, 2015 3:29 PM in response to Lagoiski

Hi All, Just a little update for you all...


Since installing CUDA as mentioned in my previous post things have actually been a little more stable (should have probably given it more time) - I'm on my 3rd day without a crash - http://www.nvidia.com/object/mac-driver-archive.html - if this works, it would point to a GPU issue. I know GPU support is an issue currently with Adobe CC apps - but in all honesty I'm really clutching at straws and still have other issues listed below...


The only things I would add, to my crash issues are:


1. Wake up - from a sleep, takes much much longer, on a similar model (lower spec) at my place of work wake up is instant where as on my mac it takes sometimes minutes.


2. And that this ALL (including the crashes) has only become an issue since upgrading the OS to Yosemite.


Has anybody else experienced these alongside the random crashes?


Thanks, Dave

May 26, 2015 7:32 PM in response to smithy_dave

Re 2: My random crashes started with Snow Leopard. Now on 10.10.3 .. still crashes. Crashes occur mostly when using Adobe lightroom - resizing crops and tone / color control brushes. Very annoying in the middle of a project.

Btw, My Graphics is the standard NVIDA GeForce GTX 675MX 1024 MB. Did you upgrade your card?

Also, am considering installing CUDA as well .. a little hesitant though. Are there any dangers?

May 26, 2015 11:55 PM in response to vanstar sydney

Hi Vanstar,


Yeah interestingly for me too, the crashes mostly happened when Dreamweaver and Illustrator are open - however using those programs the majority of the time could mean its mere coincidence.


Yeah I upgrade my mac at point of sale.


As far as CUDA is concerned I'm not going to pretend I know for sure, as everything I've learned so far has been in desperation, reports in various forums show that for some it settled crashes and others it actually makes them worse - But looking at Adobe forums its one of the first things they suggest to try. CUDA runs like an app, so if it does make things worse it can be removed pretty easily. - But please do you own research on it first.

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

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