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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Question marked as Top-ranking reply

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 28, 2015 2:26 PM in response to Lagoiski

Count me in as one more. Same late 2012, i7, 27" iMac.


About three months ago it started shutting down at random. After a shutdown, like others, it requires unplugging before it will reboot. I cannot associate the shutdowns with any software or activity, it's completely random as far as I can tell.


I took it in to the Apple Store and they kept it for about 9 or 10 days. They tell me they did all the tests but could find nothing. They finally reinstalled the OS (I'm still using Mavericks BTW) and sent me home with it. No luck, still shutting down without warning.


Wish I could offer some insight. Just another person stuck with a computer that may or may not work from one moment to the next.

Jun 5, 2015 10:32 AM in response to vanstar sydney

I am also having the same frustrating random black outs that require unplugging to restart.


I am still running Mountain Lion (10.8.5) and have only the original 8GB RAM.

iMac 27in Late 2012

3.4 GHz i7


Power supply sounded logical, but after reading that some have the same issue after replacing it and reading all the different remedies and repairs - I don't know what to think. I wish Apple would chime in with some help or answers.

Jun 5, 2015 11:47 AM in response to Lagoiski

Hi guys i'm having the same problems since last 3 days.

My iMac shut down with no apparently reason at random.


iMac

27-inch, Late 2012


3.4 GHz Intel Core i7

16 Go 1600 MHz DDR3

NVIDIA GeForce GTX 680MX 2048 Mo


I install iStat to check the performance. Don't know if it's normal but my temps of my GPU Diode is near 50°c without activity and can reach till more than 70°c with graphics softwares. Maybe this could be the reason : overheating and then shutdown to prevent any damage?


Did someone have an answer to this problem? I read all the comments above however nobody seems to have the solution.

Jun 10, 2015 11:41 AM in response to TerziniG

I have the same iMac and the same problem. Mine was fine until I installed a bad RAM, since then I have problems with my iMac shutting down when it goes to sleep or having troubles powering on without the SMC reset. Mine requires several minutes unplugged in order to start and sometimes it needs multiple tries.


Its currently in a service at an Apple reseller in my country. I will come back and let you know their diagnostic and what needs to be done. The thing that worries me s that one guy here had the logic board replaced twice and the power supply once and it still does it!!!


If fixing whatever the repair shop tells me doesn't solve it I will go at an apple store in italy for them to fix it.


However it goes I will be back and let you guys know. Make sure everyone comes back and updates this thread if they solved the issue.

Jun 13, 2015 2:42 PM in response to webdanger

Mine got back from the service provider and passed all tests, they said that unplugging and replugging 10 times worked and my iMac is not shutting down while on sleep. I am absolutely positive its a RAM issue. I had this problem while combining other OEM ram with my original ones, after a lot of testing I developed the problem. After I reinstalled the original ram that came with my mac, 8gb, it seems to work again. I think ram slots count as well, I mean you should left the ram in the slots it came in. Very strange behavior, I will test it further more and report.

Jul 18, 2015 4:24 PM in response to vanstar sydney

Same issue here; random shutdown without warning. No rhyme or reason.


late 2012 iMac 27"

3.4 intel i7

4GB Ram

GTX 680


Took to Genius bar. They had it for over a month. They replaced power supply, logic board $800. Took it home worked for two weeks without issue. Then started same symptoms all over again. I check the logs, nothing. Run the Apple hardware test, no errors. tested the ram with Rember, no errors, & run EtreCheck, nothing stands out as to the cause of this issue. Sometimes I'll be browsing with chrome or safari..shuts down. Sometimes, it shuts down while booting up! Unplug it for 15 seconds, do nothing for 10 more seconds, power on.

Really at my wits end with this iMac, this is likely my last. Really annoyed, considering I basically paid 1/3 of a new iMac to "fix" it...

Here is the Etrecheck below:


EtreCheck version: 2.2 (132)

Report generated 7/18/15, 3:09 PM

Download EtreCheck from http://etresoft.com/etrecheck


Click the [Click for support] links for help with non-Apple products.

Click the [Click for details] links for more information about that line.


Hardware Information: ℹ️

iMac (27-inch, Late 2012) (Technical Specifications)

iMac - model: iMac13,2

1 3.4 GHz Intel Core i7 CPU: 4-core

4 GB RAM Upgradeable

BANK 0/DIMM0

2 GB DDR3 1333 MHz ok

BANK 1/DIMM0

2 GB DDR3 1333 MHz ok

BANK 0/DIMM1

Empty

BANK 1/DIMM1

Empty

Bluetooth: Good - Handoff/Airdrop2 supported

Wireless: en1: 802.11 a/b/g/n


Video Information: ℹ️

NVIDIA GeForce GTX 680MX - VRAM: 2048 MB

iMac 2560 x 1440


System Software: ℹ️

OS X 10.10.4 (14E46) - Time since boot: 0:3:15


Disk Information: ℹ️

APPLE HDD WDC WD10EALX-408EA0 disk0 : (1 TB)

EFI (disk0s1) <not mounted> : 210 MB

Macintosh HD (disk0s2) / : 999.35 GB (699.76 GB free)

Recovery HD (disk0s3) <not mounted> [Recovery]: 650 MB


USB Information: ℹ️

Apple Inc. FaceTime HD Camera (Built-in)

Apple Inc. BRCM20702 Hub

Apple Inc. Bluetooth USB Host Controller


Thunderbolt Information: ℹ️

Apple Inc. thunderbolt_bus


Gatekeeper: ℹ️

Mac App Store and identified developers


Kernel Extensions: ℹ️

/Applications/Parallels Desktop.app

[not loaded] com.parallels.kext.hypervisor (10.2.1 29006 - SDK 10.7) [Click for support]

[not loaded] com.parallels.kext.netbridge (10.2.1 29006 - SDK 10.7) [Click for support]

[not loaded] com.parallels.kext.usbconnect (10.2.1 29006 - SDK 10.7) [Click for support]

[not loaded] com.parallels.kext.vnic (10.2.1 29006 - SDK 10.7) [Click for support]


/System/Library/Extensions

[loaded] com.avira.kext.FileAccessControl (1.0.0d1 - SDK 10.9) [Click for support]

[loaded] com.nvidia.CUDA (1.1.0) [Click for support]


Launch Agents: ℹ️

[loaded] com.avira.antivirus.general.agent.plist [Click for support]

[loaded] com.avira.antivirus.ipm.ui.plist [Click for support]

[loaded] com.avira.antivirus.notifications.agent.plist [Click for support]

[loaded] com.avira.antivirus.odscan.default.plist [Click for support]

[loaded] com.avira.antivirus.scheduler.agent.plist [Click for support]

[running] com.avira.antivirus.systray.plist [Click for support]

[loaded] com.avira.antivirus.telemetry.agent.plist [Click for support]

[loaded] com.avira.antivirus.update.default.plist [Click for support]

[running] com.avira.helper.avstats.plist [Click for support]

[loaded] com.nvidia.CUDASoftwareUpdate.plist [Click for support]


Launch Daemons: ℹ️

[running] com.adobe.ARM.[...].plist [Click for support]

[loaded] com.adobe.fpsaud.plist [Click for support]

[loaded] com.avira.antivirus.dbcleaner.plist [Click for support]

[failed] com.avira.antivirus.ipm.loader.plist [Click for support]

[running] com.avira.helper.watchdox.plist [Click for support]

[loaded] com.nvidia.cuda.launcher.plist [Click for support]


User Launch Agents: ℹ️

[loaded] com.adobe.ARM.[...].plist [Click for support]

[loaded] com.google.keystone.agent.plist [Click for support]

[loaded] com.valvesoftware.steamclean.plist [Click for support]


User Login Items: ℹ️

Steam Application (/Applications/Steam.app)

iTunesHelper Application (/Applications/iTunes.app/Contents/MacOS/iTunesHelper.app)

Degrees UNKNOWN (missing value)

AdobeResourceSynchronizer Application Hidden (/Applications/Adobe Reader.app/Contents/Support/AdobeResourceSynchronizer.app)


Internet Plug-ins: ℹ️

FlashPlayer-10.6: Version: 18.0.0.209 - SDK 10.6 [Click for support]

QuickTime Plugin: Version: 7.7.3

AdobePDFViewerNPAPI: Version: 11.0.12 - SDK 10.6 [Click for support]

AdobePDFViewer: Version: 11.0.12 - SDK 10.6 [Click for support]

Flash Player: Version: 18.0.0.209 - SDK 10.6 [Click for support]

Default Browser: Version: 600 - SDK 10.10

F5 SSL VPN Plugin: Version: 7070.2012.1026.1 [Click for support]


Safari Extensions: ℹ️

Open in Internet Explorer


3rd Party Preference Panes: ℹ️

CUDA Preferences [Click for support]

Flash Player [Click for support]


Time Machine: ℹ️

Skip System Files: NO

Mobile backups: OFF

Auto backup: NO - Auto backup turned off

Volumes being backed up:

Macintosh HD: Disk size: 999.35 GB Disk used: 299.58 GB

Destinations:

Time Capsule [Network]

Total size: 2.00 TB

Total number of backups: 66

Oldest backup: 2013-05-30 07:35:04 +0000

Last backup: 2015-06-20 03:42:00 +0000

Size of backup disk: Adequate

Backup size 2.00 TB > (Disk used 299.58 GB X 3)


Top Processes by CPU: ℹ️

44% mdworker(2)

2% WindowServer

2% fontd

0% steam_osx(2)

0% savapi


Top Processes by Memory: ℹ️

497 MB kernel_task

340 MB savapi

315 MB avguard.bin

90 MB steam_osx(2)

74 MB ocspd


Virtual Memory Information: ℹ️

548 MB Free RAM

3.46 GB Used RAM

0 B Swap Used


Diagnostics Information: ℹ️

Jul 18, 2015, 03:04:41 PM Self test - passed

Jul 18, 2015, 02:17:06 PM /Library/Logs/DiagnosticReports/com.apple.WebKit.WebContent_2015-07-18-141706_[ redacted].hang

Jul 18, 2015 9:21 PM in response to cessnapilt172

Thanks for your Entrecheck run. Here's what I learned:


1. While 4GB RAM is sufficient for many users, doubling the RAM will increase the speed and possibly the stability of your system - especially with the latest Mac OS. The fact that nearly all of the virtual RAM is used suggests you need a more physical RAM.

2. Avira Antivirus is probably unneeded, and seems to be using a lot of system resources. I'd remove Avira, preferably with an uninstaller.


Do you have any readings re: the heat on your machine? Can you post them here? iStat is a quick way to get these readings.

Jul 21, 2015 11:52 PM in response to Solidairs

Unbelievably (And just my luck), I have the same model at work, which over the last week has just started to randomly crash like my home one. As mentioned before the home mac hasn't crashed since installing CUDA, so I'm going to try the same fix on the machine at work and if successful, will post step by step of all the actions taken. Hopefully I'm right on this, but will update ASAP.

This thread has been closed by the system or the community team. You may vote for any posts you find helpful, or search the Community for additional answers.

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

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