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27-inch / 27" iMac Random Shut down

SPECS:____________________________________________________________________________
• 27" 2.8 GHz Intel Core i7 / 8gig / 1TB
• OS 10.6.3 (about to update to 10.6.4)
• All firmware updates have been applied according to software update
• 3 external drives: 1-320 gig 800fw / 1-TB USB 2.0 / 1-500gig USB 2.0

INFORMATION:____________________________________________________________________

I've been running with this configuration ( 3 extra drives) since approximately December with no issues. Out of the blue... only running Aperture and Safari - my iMac JUST SHUTS off- WITHOUTwarning. It acted as though I was running a MacBook and the battery going dead/asleep. That's how random and sudden it shut down - NO WARNING. I did have the iMac asleep for about three hours before coming back to it to start working again when it shut down, but it should have even been cool.

I only started reading around on the web to see of other incidents after this random shut down this evening, but I can't find anything specific. I've found A LOT of similar things - all seemingly related to "HEAT."

And heat seems to be a certain issue recently - in the last day or two. Today I noticed my top back side to be hot, which isn't uncommon, however, it became so hot I really wasn't able to keep my hand on the top back. I've also noticed A LOT of spinning beach balls, and lots of processor delay! Heat??

There are NO energy saver pref's set to automatically shut it down. The power was and is firmly set. There are no network settings, nor access to the iMac to have it shut down. It is not shared with anyone on the network.

SUMMARY:___________________________________________________________________________

• Today, I grabbed a couple temp / monitor widgets and am trying to watch the data. All components seem to be at/around/below 140 degrees F with ambient air at 77 degrees. I don't know numbers, but that all seems reasonable.
• Going to update to OS 10.6.4 (doubt that's it!!)
• I'm going to run the hardware test from my disc to see if ANYTHING. 8-p
• AND... I'm going to call Apple to set up a case. It's still full under warranty, and I have 2 more years of AppleCare on it. But there's been too many things pointing to hardware to call this a software issue.

I've dodged all the display issues with my iMac, but now.. I'm a bit hacked knowing how much I spent on this thing, with the initial DELAYS I went through, ordering it before it had even been released!

?? QUESTION ??_____________________________________________________________________

So, has anyone else been having this issue, heard of a solution, seen anything on Apple's website of known issues ??

Barry
( Grumbling bout my Mac)

Which one of twelve??, Mac OS X (10.5.6), ever hear Newton?!! ;-) One of those, too!

Posted on Jun 22, 2010 8:59 PM

534 replies

Sep 23, 2010 10:24 AM in response to Berry with an A

@Berry with an "A"
Thanks for your thorough report. My iMac is new and I have had four spontaneous shutdowns since September 2. I will try giving it the cold - hard - boot (and deplete the capacitors, too). I didn't know it was called an SMC reset and not sure why Apple would call this a last resort ( http://support.apple.com/kb/ht3964), except to save data, which obviously ain't happening if it has already shutdown. But as soon as I get home tonight, I am giving it a try.

Sep 24, 2010 7:31 AM in response to Berry with an A

FWIW, I'm having same issue with same setup. Four random shut downs in two days. Gonna try solution listed below, hope it works!

dopepope

Level 1

4 points

Sep 24, 2010 8:41 PM in response to intraosseous

I just did the SMC reset thing, and with in 2 minutes my computer shut itself off. This is pretty serious.
It's the 3rd random shut down in 2 days. I've only had the computer about 10 days.

Sep 24, 2010 9:51 PM in response to dopepope

Well, I did the SMC reset after my iMac randomly powered down for the second time today. Within an hour I had another power down. This stinks! I'm almost tempted to bring my 24" iMac back to the studio so I don't have this issue.

Also, after reading some of the other replies above, I've noticed the top surface gets really, really, hot. And it doesn't take a long time to get hot either. Wondering if that has anything to do with this issue? I am also tempted to remove the 16GB of RAM and go back to what the iMac came with to see if that has anything to do with it. The RAM I bought was the OWC NuRAM (16.0GB (4x4.0GB) NuRAM PC3-10600 DDR3 1333MHz SO-DIMM 204 Pin CL9 SO-DIMM Memory Upgrade Kit for Mid 2010 21.5" & 27" iMac Models. Lifetime Replacement Warranty).

mcsys

Level 1

2 points

Sep 25, 2010 1:18 AM in response to intraosseous

intraosseous, Rojer W.W & burkanov issues are very similar our problems.

http://discussions.apple.com/thread.jspa?threadID=2567907&tstart=15
http://discussions.apple.com/thread.jspa?threadID=2588800&tstart=15
http://discussions.apple.com/thread.jspa?threadID=2548180&tstart=150

I believe if you decrease your RAM, it should solve your shut down problem.

If you guys on 16GB, most likely we are on the same ship.
1. myself
2. Sjohnson803
3. Jeff.C
4. TheAnimist
5. tck49
6. myror
7. labeck
8. peterwillem
9. normal1

Sep 25, 2010 2:40 AM in response to mcsys

Ok,
but I did not buy 16 Gig of ram for only using 8 of it. My iMac is supposed to support 16 Gig according to Apple. Look at their web site. So if it does not they should do something about it!

peterwillem

dopepope

Level 1

4 points

Sep 25, 2010 9:41 AM in response to peterwillem

I totally agree. I chose the 16gb of ram purposely to help alleviate the pressures of 3D work. I chose this entire workhorse set up for the large file artwork I do. Spontaneous shutdowns weren't part of the deal.

dopepope

Level 1

4 points

Sep 25, 2010 11:25 AM in response to dopepope

If it means anything, I realized I was watching video every time I experienced a spontaneous shutdown. The 1st, I was watching a youTube. The 2nd and 3rd times I was watching a windows media player clip. Perhaps is a graphics card issue?

Sep 25, 2010 11:48 AM in response to dopepope

Actually most "blackouts" occurred when I was not behind the computer, some did occur when I was using mail or safari. Anyhow no tenuous operations.
Anyhow I have been using 8 Gig of ram for the last two weeks( for testing it) and everything went fine ,no problems whatsoever . So don't think it is the graphic card.

peterwillem

Message was edited by: peterwillem

mcsys

Level 1

2 points

Sep 25, 2010 7:02 PM in response to dopepope

Understand you guys frustrations, but we can't leave it randomly shut down as it will not speed up our work either. We have to find a quick solution to get our work done asap.

To date, my first iMac i5 & i7 are having issue with 16GB & now running with 8GB perfectly. My recent iMac i5 is running with Transcend 16GB without issue yet. I suspect is the chip set used on 4GB RAM. I can't confirm my findings.

dopepope

Level 1

4 points

Sep 26, 2010 12:45 PM in response to mcsys

So I had my 4th random shut down last night. The consensus seems to lean towards a heat issue, but my situation is making that difficult for me to believe. I wasn't doing anything strenuous at all on the computer when it shut down this 4th time. I was typing a word into an email subject line. I have a tall vertical fan set up to ventilate my entire work station, blowing directly onto the backs of my iMac 27" i7, and the secondary monitor I use for pallets. I also have been sliding my hand along the back of my machine quite often since troubleshooting for this problem, and it wasn't hot to the touch at all just moments before this shut down. In fact, it's never hotter than just warm. That SMC fix didn't do the trick. The fan isn't doing the trick. I'm beginning to think taking out 8gb of ram (I have 16gb) won't even help because earlier complaints describe their systems having 8gb and still being affected.

Sep 26, 2010 2:50 PM in response to dopepope

Well from what I have read in other threads/postings about this issue and my own experience (I have not had any sudden shutdowns for 16 days since using less than 16 gigs) iMacs with less than 16 Gig (8 or 12 Gigs) do not have the problem of sudden shut downs.
So I don't think it is a matter of to much heat.

peterwillem

dopepope

Level 1

4 points

Sep 26, 2010 2:54 PM in response to peterwillem

On the contrary, the very first post that began this thread is a computer with 8gb. So, it does affect computers with less than 16bg ram.

Sep 26, 2010 3:22 PM in response to dopepope

It appears we are talking about different iMac models. I am talking about the Imac mid 2010 27" i5/i7 , while you are talking about the model before that.
And if you read the threads about the mid 2010 model you will see that the problem does not occur when using < 16 gig ram. See these threads:

<a class="jive-link-external-small" href="http://">http://discussions.apple.com/thread.jspa?threadID=2560826&tstart =75
http://discussions.apple.com/thread.jspa?threadID=2592483&tstart=0
http://discussions.apple.com/thread.jspa?threadID=2548180&tstart=0
http://discussions.apple.com/thread.jspa?threadID=2588800&tstart=15

All mid 2010 iMacs, all the same > gig problem.

peterwillem

Sep 27, 2010 10:42 AM in response to peterwillem

peterwillem said,
"iMacs with less than 16 Gig (8 or 12 Gigs) do not have the problem of sudden shut downs. So I don't think it is a matter of to much heat."

You are posting incorrect and/or inaccurate information. Maybe you should start a new thread, specifically for the newer model iMac? I actually started this post. I'm not saying "it's MY thread," but what I am saying is... you're posting inaccurate and irrelevant info for the model and configuration that this thread was regarding.

This issue in fact DOES effect last Nov/Dec 's first i5 i7 models. I have the first i7 model, which is not at all much different than the ones just released a few months ago.

Regardless... I have the first model, with ONLY 8 gigs of RAM direct from Apple, and I did in fact have had the unexpected shut down issue in the past. During that time I also experienced a seemingly amount of abnormal heat, sometimes during under video use, and sometimes very minimal processor use.

I have, however, already indicated that the SMC reset corrected my issue, and I can still report I've not had any issues since reporting it here within this thread. This was done when I made sure ALL updates had been done on my iMac, including the SMC firmware update from earlier this year. The SMC firware update is why I suspect my iMac had issues and needed to reset the SMC.

I have spoken with the highest level tech support at Apple as well. In fact, they made it a point to call ME, at my office. I think Apple may believe they have the issue under control as I've tried to contact the tech whom I spoke with - with his direct contact info, but he has not bothered to reply.

I think there's obviously still something going on - but I do not think it's limited to last winter's model, or the one's recently released. It's obviously effecting both, and it appears to be not limited to just a power or memory issue.

27-inch / 27" iMac Random Shut down