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

I Had my iMac looked at for random shutting down and was told it's a bad video card and there was a recall on it for 2011-12 models. I have to find out if mine is covered.

I believe that was specifically to do with AMD graphics chips on the older 2011 - 2012 iMacs. This could be a similar issue though with Nvidia graphics cards instead.

https://support.apple.com/en-gb/HT203787

Quick update...

Updated by Genius Bar representative that they were unable to replicate the intermittent shutdowns using their power cable and they will run the same series of tests using the power cable I provided.

This information is completely contradictory to what I was informed of less than 24 hours ago. That being, the shutdown issue was replicated and the system is being serviced for logic board replacement.

The representative understood my concern regarding this contradiction, and will attempt to determine if the issue was in fact replicated. He also suggested they may replace the logic board regardless of what is determined.

I'm glad the hardware issue was replicated, and your machine will be serviced.

About your concern that initial information you received was "completely contradictory." I think many are in your situation are in a similar quandary. For some, it's a software issue, the logic board, a faulty fusion drive, or something else. I hope you'll post back with your results.

Hi, I have had a very similar issue with my late-2012 27" iMac and have been following along here for a month or so.

27-inch, Late 2012

3.4 GHz Intel Core i7

16 GB 1600 MHz DDR3

NVIDIA GeForce GTX 680MX 2048 MB

Fusion Drive 1TB

Since I bought the system in early 2013 there were a few times my son had some freezing issues playing 3d games but never anything that wasn't fixed with a restart and I just wrote it off to driver problems or issues with the game.

Mid-summer this year I began to experience the system locking up with video artifacts filling the screen(small red and green squares mostly, sometimes others). It would happen during any system intensive task such as video editing or rendering, photoshop work, etc. 99% of the time I would have to reboot manually and even then most times the system would refuse to reboot, hanging with a few light graphic artifacts appearing during the grey screen with the progress bar. Resetting PRAM etc would not help and going into hardware diagnostics would not report any issues (even though the Hardware Diag. screens would occasionally have graphic artifacts or flashing colours themselves) The only thing that seemed to get things running again was leaving the the system off for a while and then rebooting. Over the course of a month I tried just about everything - different video drivers, installing the El Capitan beta, reinstalling a completely clean OS etc - without any any luck in resolving the issue. The odd time a panic log was generated it seemed to show the video drivers were the source of the problem.

I eventually found I was able to replicate the problem 100% percent of the time by running GpuTest's FurMark. As soon as the GPU Temp reached 70-80 C the system would hang with extensive video artifacts etc. It seemed like a classic case of a GPU or video memory failure due to a solder joint, very similar to the issues the led to the 2011 Macbook GPU replacement program. Everyone I consulted said that logic board replacement was my only option. Unfortunately it is not under warranty so the cost would be extremely high. I ended up pickup up a new iMac just so I could keep working, figuring eventually I would get the logic board replaced so I could sell or repurpose the system (and probably hoping Apple would announce a replacement program).

Now the interesting part - Wednesday I had some spare time so I replaced the El Capitan beta on that system with a clean instal of the full release version. Since then the system has been on full-time and I cannot replicate the issue at all, either through normal usage or running GpuTest/other system stress tests. FurMark has been running on that system almost constantly during each day with the GPU temp hitting 90-93 C. Occasionally when I stop and restart the test there is a very brief graphical glitch for a split second and then the test runs fine. Other than the updated OS the only thing I can think may be a factor is that the system had been turned off for 4-5 days before the El Cap install.

Any thoughts? If the issue does come back I will post an update.

Further Update:

As in my last update, a Genius Bar representative informed me that they were unable to replicate the intermittent shutdowns. However, I inquired as to what tests are being performed as well as what diagnostic information they are attempting to gather. They informed me that the OS logs each time the system is shutdown (manually or unexpectedly). With each documented shutdown, there is a code that identifies the reason. The logged code associated with an intermittent shutdown is what they were after in the attempt to replicate the problem. I wish I had asked this question earlier...

While on the phone with the representative, I immediately isolated a date and time during which I experienced an intermittent shutdown. He was able to locate said shutdown in the OS log. He looked up the associated log/code and determined it was related to a sudden/unexpected loss of power to the system. As the system has been used in the same outlet along other devices (i.e., electric cycling training, a laptop, external monitors, etc), this finding appeared to lend some support to a faulty iMac power supply and/or system power cable, and not the environment in which it is used.

Apple Support is now replacing the power supply and providing a new system cable to remedy the situation. I should have the system back this week, and I will update with any additional findings.

I wish users would follow your advice analyzing and poring over these iMac issues. Moreover, I believe that the Apple representative probably made the correct diagnosis by replacing the power supply.

However, the vintage of your machine apparently makes it potentially vulnerable to this problem. You probably know that a trip to the Apple Store won't fix it forever. That's why aggressive heat management may be your best long-term solution. These high-end iMacs really generate heat, and it can concentrate in vulnerable areas like the logic board, graphics board, hard drive, and power supply. During gaming or video rendering, heat can come close to 200 degrees F. At the least, these temperatures can weaken solder and flux.

Several applications can alleviate heat problems. I use iStat Menus, but there are several other options - a few even free. Never allow your temperatures to rise above 165 degrees F for any reason. If the temps rise too high, increase the fans to compensate. Don't assume that your iMac will do it automatically.

>> Hi, I have had a very similar issue with my late-2012 27" iMac and have been following along here for a month or so.

Sorry, I just realized I had meant to submit the post referenced above in a different thread more related to my video issues with the 2012 27" iMacs. It doesn't have much to do with power related crashes but it does not seem I can remove it. C

I am another victim of iMac 27" Late 2012 random shutdowns which neither Apple Store nor a Premium Reseller are able to replicate the problem in order to find a solution.

I have tried and done everything with no solution

HD test passed with no problem

Reset SMC everytime the computer shuts down which is something very frustrating and annoying

Install OS

Files and software not original removed and the shutdown keeps happening (NOT A SOFTWARE PROBLEM)

1 visit to apple store and they could not see what the problem was because the computer was working owell there

2 visits to premium reseller with the same conclusion and to my surprise their are not even concerned about this magical shutdowns

(I am thinking about having an office in an apple store where I can go to work with mi imac because in my house is impossible)

I think Apple cannot avoid these posts, this discussion is taking place in their own official support forum. There are plenty of cases like ours and Apple is ignoring us.

Exactly my situation.

Seven pages of posts on the same issue. Sometimes, it's a good time to look over the evidence and see where it's going.

Here's what I learned:

- The issue seems to happen to certain 2012 27” iMac i5 and i7 - but they're not the only machines affected.

- The problem is exacerbated by high-temperature rendering and use of Adobe software, like Lightroom, Dreamweaver, and Illustrator.

- The problem happens "all of a sudden" and doesn't get better by itself. The problem usually appears about two years after purchase.

- Replacement of some hardware, like the graphics or logic board doesn't necessarily solve the issue.

- Apple repairs have been inconsistent - including logic board, graphics board, and power supply replacement. No solutions seem to last.

- It's not a software problem.

- The problem varies in severity, from occasion to as many as ten times a day.

Certain fixes don't work consistently, or at all:

- replacing RAM

- installing CUDA, though that might solve things for a short time

- PRAM reset

- power supply replacement

- logic/graphics board replacement

Some have noticed:

- The problem frequently happens at high temperatures - like 80 degrees C

- TechTool suggests that the electrical output from the sensors may exceed an acceptable range.

- The longer an affected iMac is unplugged, the longer you can use your machine before the problem recurs.

Here's what I learned:

1. The problem is not isolated to this "vintage" of iMac. Some owners of 2013 iMacs are reporting the same issue. The problem starts to appear around two or so years after manufacture.

2. The problem is exacerbated by extended rendering, or extended use of graphics software like Lightroom, Dreamweaver, and Illustrator.

3. Once the problem appears, it doesn't seem to get better by itself. In other words, the damage has already happened (whatever that damage is).

4. For some (but not all affected machines), the pattern follows the classic appearance of a power supply failure.

There are lots of questions I'd like to ask affected users:

- How often do you use your fans? Do you use them aggressively?

- Do you use your Mac for long, intensive rendering work?

- Have any users tried fixing their machines with a technique that seems to fix with similarly-affected MacBooks - a BGA re-ball?

An Additional Update:

Since obtaining my system from repair (i.e., power supply and power cord replacement) over a week ago, I have not experienced an intermittent shutdown.

I suggest obtaining the shutdown code that is associated with an intermittent shutdown. In my situation, as soon as the Genius Bar representative had this code, he was able to make a diagnosis and propose a repair solution. Granted, I am still under Applecare and that may have been a factor in his little hesitation to repair the system. Prior to obtaining this code, the Genius Bar was unable to replicate the issue.

Finally, although I may or not be in the clear and that each situation has similarities and differences, I'm thus far satisfied with how Apple, specifically Matt (Genius Bar Representative) at the Northbrook, IL location, handled my system's issue.

And yet another one to be added to the list...

iMac 27-inch, Late 2012

3,4 GHz i7

32 GB RAM

3TB Fusion drive

NVIDIA GeForce GTX 675MX 1024 MB

The (sudden) shutdowns started the day after I updated the system to 10.10.6 and added RAM. The following was tried, to no avail:

-Replaced RAM with the original modules

-Clean install of the system (as a result of the 3TB hard drive replacement program)

-Joined the Apple Beta testing program to see if the newest El Capitan builds would help.

I can reproduce all of the behaviors that seem characteristic to the issue: sudden, random shutdowns; turning on only after pulling the plug for at least 5 minutes; the longer the plug is pulled, the longer the computer works; PRAM reset triggers the shutdown, etc.

Will take the computer to service this week (Amsterdam) and will reference this discussion. I would like to have the power supply replaced, as this is the most logical solution, according to my electronics-savvy friends.

this thread may be relevant to our interests My imac keeps restarting and freezes on grey screen with safe mode restart

Great list.

I've had the exactly same problem all while I was supposed to deliver a job. I'm a visual effects artist and was hitting the computer with renders and it was basically restarting every 15 mins.

my specs are like everybody else's

Mac (27-inch, Late 2012)

3.4 GHz Intel Core i7

NVIDIA GeForce GTX 680MX 2048 MB

After two weeks of multiple kernal panics, reboots, reinstalling the system, getting the apple store to replace the logic board, "downgrading" to Mavericks, replacing RAM and ultimately having to buy a new iMac to finish my work. I've since put the new computer aside and started over. I'm convinced it has to do with the GPU. I haven't installed the CUDA drivers and there fore my programs aren't putting any pressure on the GPU. It's running good so far. I'll post again in a week and a half after 18/hr a day rendering and use.