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

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.

After hours with Tech support (as helpful or as unhelpful as they could be, given this situation) and studying the many responses and attempts on this board to remedy the similar problem I faced with my 27" iMac (late 2012. 2.9 GHz Intel Core i5) after installing El Capitan, I decided to try a solution for myself: erase and the HD and start over from factory settings. Fortunately, I was able to back up all the most pertinent files I needed---most, but not all---before starting over. I gradually updated OS through to Mavericks; including all updates, and my computer is running perfectly. It's been three days, and it's running as if new: no crashes, no slow response time, no beach balls. I'm considering expanding the experiment to downloading Yosemite. But only after I can complete some work at hand.

It was very disappointing that Tech Support was unable to help; this problem seems alien to them, in spite of my forwarding this lengthy and important thread to the senior tech advisors I spoke with. Even stranger, my computer didn't qualify for a replacement HD, according to the serial number I have.

I arrived at making the decision to erase the HD partition only after many attempts to solve the issue, either through advice from Tech staff or my own research, i.e. restoring from my most recent Time Machine backup. All previous solutions (no, I was not going to bring my machine into the store only to be told what so many others were told, that there wasn't a problem, or to be sold some new temporary fix) did not work and/or worsened the problem.

If Apple were made to be as responsible to the problems their machines face as any American car company would, we'd have some answers. The late model 27" iMacs are not equipped to deal with the recent upgrades, in particular, El Capitan. A hypothesis, only, as I've still more experimentation to do. But just my two cents on this sad, frustrating issue.

I am done the same thing today, format my hard disc and reinstall the OS El Capitan. I have contacted the Apple tech support .He has told me that to use time machine to restore the data. Unfortunately, everything was busted during the Transferring Your Information screen. My iMac is shutdown during the process. Pretty much, I am not able to restore the data from Time Machine. I couldn't restore the data one by one, as the Time Machine data is pretty much stored as a snap shot of your system.

I am very disappointed about the this model of iMac (late 2012 27 inch iMac). This may be the first generation of the Slim iMacs, therefore there are lot of issues about this generation. I strongly urged Apple to find out the solution to fix this iMac. As this is not a cheap investment, I spent 3300 AUD for iMac which doesn't last for 2 and half year. That seems ridiculous. My old 24 inch iMac is still running OK, it is just a bit slow. The build quality has been dropped so much. Is that related to Chinese Manufactory?

You can add another iMac 27" 2012 frustrated owner.  Have taken it to the apple representative for the third time now.  First, they replaced the logic board.  It worked for about a month or so.  Problem started again.  Took it for the second time: they replaced the power supply.  Worked for about a week, and the machine is now at the repair service for the third time.  It's been there for a month now, and the technician tells me they cannot find anything wrong on the machine.  This is nervous breaking.  I've only had the machine for a year, and I am afraid it's been an expensive waste of money

Another victim over here

For several months my iMac (late 2012 27 inch i7 with 3TB Fusion) is not usable for work anymore... I've replaced the Fusion Drive but the problem now occurs even more than before.

Support is ignoring this problem. Even if you point them to these topics on their own forums! I've sended them error reports from the console, but they just go on with their list to reset everything. "Did you reset the NVRAM?"

For me this is a clearly a hardware problem with the new design iMac introduced in late 2012. People can make mistakes, but this is highly frustrating as this is not a cheap machine. Apple should really act and stop ignoring these huge problems.

But I'm a bit relieved I'm not the only one with this weird problem.

I have the exact same issue like other buddies in this group.

My spec is:

Late 2012, 27"

3.2GHz Quad-Core Intel Core i5

8GB 1600MHz DDR3 SDRAM-2X4GB

1TB Fusion Drive

Nvidia GeForce GTX 675MX 1G GDDR5

I have the same issue as everyone else. Started about a month ago.

iMac (27-inch, Late 2012) - purchased Apr '13 in UK

2.9 GHz Intel Core i5

8 GB 1600 MHz DDR3

Macintosh HD 1TB SATA

NVIDIA GeForce GTX 660M 512 MB

I have a Genius Bar appointment this Sunday (13th Dec) will update if anything positive comes from this.

I have the same problem as everyone else. Support isn't any help. This should be a recall issue.