27" Core i7 iMac blacks out then restarts itself for no reason...

I'm sorry I can feel your pain. I'm afraid you are in for a world of hurt like me. I have been without my imac now for 2 weeks. I have absolutely no confidence in apple support at this time and believe I am just going to have to fight to get a replacement system. Brought the machine back in after they failed to fix it the first time (10 day wait). Today I got a call that they need to troubleshoot it for another 3-5 day and cant replicate the issue. Keep in mind that I sat down with a tech and showed the issue (scrolling in lightroom) and got the computer to restart 3 different time while he watched. They also mentioned that a test showed some distortion on the video card so they were going to replace that. I really think that they are not scrolling in lightroom to replicate the issue - just running their tests.

I am very disappointed as a lifelong mac user and a stock holder that their service is so bad.

Remember to take notes and represent your case well with them. I will try to update as things unfold.

I'm wondering if it exists a kind of report automatically generated by the system when a crash happens.
We may find a clue inside such log file don't you think ?

After 13 days without a computer and a hard drive fan, LCD, PSU, motherboard, video card replacement my computer is back from apple. So far no restarts. I know I just jinxed myself but we will see. Anyway this clearly is a hardware issue that I thought was related to RAM but I think the issues are larger. I'll update if anything changes. But any other issues and I am getting a replacement.

I've gone a couple of days without a restart. I stopped using Facebook in Safari and that may have been the culprit for me. As ridiculous as that sounds... I've come across others complain about Facebook restarting their machine in other forums so... yeah. All is well in Firefox (even though I prefer Safari as a browser).

If I get another restart while not in Facebook in Safari, I'll let you guys know. But for now, I think I've pinpointed where my issues lie (once again, as ridiculous as that sounds... Facebook restarting the whole computer!?!?!)

We have the same problem here in Germany with an imac27 i7 with 8GB RAM. We got our system in January and the first weeks everything works fine. The sudden shutdowns started 4 weeks ago in February, may be after installing, the graphics firmware update. The sudden shutdown cames sometimes when browsing the web and also when working with Final Cut Pro. Its anoying. We tried PRAM Reset, SMC ... new installation of Snow leopard .. nothing helps. Now sending back the machine to apple. We hope to get it back asap.

Message was edited by: fraban

Same here in Austria with an imac27" i5; sudden shutdowns while browsing the web; immediate restarts afterwards; between shutdowns may be weeks or just days.

What kind of energy saver settings are people using? I read somewhere that putting the energy setting to default has helped a few people. I'm still convinced Facebook in Safari was a problem for me because I have been problem free since I switched over to Firefox. (There was a recent Safari update... I wonder if that fixed things. I'm not too keen on experimenting right now though).

This all said, a couple of people have had reset issues in Final Cut Pro (a program I don't use). Strange.

Possible causes of random resets in 27" iMac (i5 or i7):

- Using Facebook in Safari
- Using Final Cut Pro
- 8GB Ram upgrade
- Energy Saver settings

Possible solutions:

- Use another web browser
- Reset PRAM http://support.apple.com/kb/HT1379
- Reset SMC http://support.apple.com/kb/HT1543
- Put Energy Saver settings to default
- Remove the 4 gigs extra gigs of RAM that you bought

This all said, these solutions are more workarounds than anything else. I don't want to be limited to a certain browser, lower RAM or Energy Saver settings that don't fit my needs. Apple, please reply.

Hi Dremann,

I'm using Chrome since the beginning and never used Safari but had the problem just after the 8 Gb RAM upgrade.

My feeling was that the reset appears when I was scrolling violently a large amount of pictures in:
-Lightroom
-iTunes
-iPhotos

Could be a problem of code? Let's say when more than 4 Gb of RAM are required a call to supplementary RAM make a crash? I'm back to 4 Gb now and no restart so far, will keep you posted if it happens again.
I'm on default settings for the energy saver.

Hmmm, the 8 gb ram thing seems to be fairly consistent. I refuse to take out the RAM for now considering everyone I've talked to says it is compatible. So does the iMac (no problems found in system profiler, etc.).

My last week has been pretty good. I started using Facebook in Safari again and it didn't crash for days and I was happy until 10 minutes ago when it happened again. Not sure what was up. It seems listing programs matters little but Safari, InDesign, Adium were all open.

Bah.

I'd like to add my voice to the chorus here. My brand-new i7 27" iMac has just started randomly shutting down/restarting. I've had it about a month.

I've tried the SMC / PRAM resets with (obviously) no luck.

Not looking forward to hauling it over to the Apple store or whatever, but judging from the conversation here and other forums, this seems like this is a fairly common problem.

I did see some other threads where the culprit turned out to be a cable:
http://discussions.apple.com/thread.jspa?messageID=9202685

But it's hard to know if that's the issue here.

I also have 8GB of RAM (all Apple-installed.)

I made a big fuss to get my boss to buy me an iMac 27". After TWO swaps I was still having this problem and ended up getting a refund and resorting to a company Dell running Windows. This whole situation damaged my credibility at my company and pretty much ensured that my boss will never ever try a Mac again. Thanks, Apple.

PS. Six Sigma. You should look into it.

update - sent my 27" back to my dealer. Today they told me, they are changing logic board, the error was located there. More I did not know. Now waiting until the 27" is back.

ISSUE: Random shut downs.
SPECIS: 27" quad core i7, 8gigs/1TB

I'm adding my two bits here, too! Mine does NOT shut down AND restart. It just randomly shuts down. I applied the SMC firmware update approximately five weeks ago, and now have had two shut downs since then, but NEVER BEFORE.

I have a feeling it's been since the last couple firmware updates that have been the culprit. But I've also read logic board, and the cable connecting the logic board to the optical drive.

I talked to a Sr. tech and he asked if mine restarts, too. Funny though... I had NOT mentioned anything about restarts, too, but he asked. Now with other forum comments - I see why he asked. He said it might be because of the many periph's I have attached, but reading other comments - I doubt that. He also mentioned resetting the SMC may in fact resolve the issue, but again, after reading comments - I doubt that, too.

I know others have cross referenced other posts, but I'm going to also do it as well, with the one I started regarding just random shut downs, and including this current one.

I suggest everyone start and keep this cross reference list and maybe paste it at the end of everyone of your own posts in each of these forums, as well as new ones that most likely will appear. Maybe Apple will have to pay attention!

27-inch / 27" iMac Random Shut down:
http://discussions.apple.com/thread.jspa?messageID=11791328#11791328

Random Restarts on Intel based iMac
http://discussions.apple.com/thread.jspa?threadID=1943134&start=0&tstart=0

Sudden restarts and shutdowns on iMac
http://discussions.apple.com/thread.jspa?threadID=1865839&start=0&tstart=0

And this current one here: 27" Core i7 iMac blacks out then restarts itself for no reason:
http://discussions.apple.com/thread.jspa?threadID=2258132&start=0&tstart=0

I get the blackout without the restarts and tried all the suggested remedies on these forums with no relief.

I had this same problem (blackout, restart) appear recently after months of flawless function, which seemed to start shortly after adding 2 sticks of RAM to bring the total up to 8 gigs. All 8 gigs showed up in System profiler.
In my case the problem was repeatable- it occurred every time I tried to upload a book in Aperture 3. Before the added RAM no problem. This makes it easier to diagnose.
I pulled the new RAM and the problem disappeared. I then swapped the original RAM with the new RAM. Still no problem. So both sets of RAM work. I then reinstalled all 4 sticks of RAM. No problem so far. I did open almost every program on my computer and had many of them playing or processing data to push the RAM until I could see that there was no free memory available. It's been a few days with no problem and I will be uploading another book soon. My impression was that it was simply reseating the RAM that fixed the problem.