27-inch / 27" iMac Random Shut down

Crap, I have the same symptoms, but a WD hard drive. I have to admit that shutdowns on this machine are fewer than many people have discribed. I get maybe one a week, but shutdowns at critical times are frustrating to say the least, sometimes go a month without one. Someone else mentioned that this maybe a hard drive or bus connection problem not a hard drive problem. Could it be the WD hard drives are less susceptable to this connection problem then the Seagates?

I have weekly crashes and seemingly continuus disk corruption with a WD20EARS drive.

My iMac just started turning itself off. I have read all 32 pages of complaints and feel my situation might help someone, who is knowledgeable with these computers, in diagnosing the problem.

I don't feel "heat" has anything to do with the problem, as my computer will shut off only minutes after starting (just about the time it takes to load my desktop.... the cumputer cuts out like it had been unplugged).

Here is what is interesting about my situation. Like the rest of you, I had to unplug the computer for a while and then plug it back in before it wouldstart up agian. However, today I wanted to upgrade from OS X 10.4.11 (I think it's called "tiger") to "leopard" 10.5 (not snow leopard).

My 2009 iMac shuts down without warning too. So far it seems to only do it when I'm browsing with Safari. I don't have Java enabled, but I do have Java on my machine. I'm assuming it must be something a bug with Safari.

I have an early 2010 27" iMac (3.06 GHz, Intel Core 2 Duo, 4 GB stock RAM) that just started up this nonsense about a month ago. Absolutely no problems in almost 3 years until a week before Christmas. Did some initial troubleshooting (SMC reset, running SMC fan control, PRAM reset, disk permissions repairs, yada yada yada) and got 2 - 3 weeks of uninterrupted use. Then, this last week it started randomly shutting down and attempting to restart (about 3 times after the initial crash) before just remaining a black screen, though sounding like it's still running. Reran the same battery of troubleshooting, plus logging each additional incident (what I was running, etc.). You know, to mix and match to try to isolate if it's an application causing the problem. Can't seem to find that it's one in particular. Never any error reports, kernel panics, or anything like that logged. Finally, last night it entered it's crash/restart cycle and seemed to be dead. Talked with an Apple Tech, who listened to all that I had done and told me that my only option was to take it to a service provider. Awesome. They tried to have me start it up to immediately evalute the hard drive (holding the "D" key at start up) to no avail. After getting off the phone with Apple, I could still here the iMac "running" (black screen). After 5 minutes, it finally chimes and starts up like nothing was wrong.

I've run every system diagnostic I know to run and having read most of 32 pages of people dealing with this issue, I have little hope that I will ever figure out on my own or that an Apple tech will figure out the problem to properly fix it. Barry's final post said as much. But since I live in a country without an Apple store/service provider, I did have a few questions to throw out there to see if there was a way for me to check before trying to lug this thing back over the Atlantic to have it looked at:

1. When I check the HD, it says that it "appears to be OK." Does this include an evaluation of the logic board or is there a separate diagnostic I can use to evaluate the logic board? (as it seems from reading that this may be the culprit)

2. Has anyone just erased their HD, restored it to factory condition, and only incrementally re-introduced files and software to their iMac? If so, did the problem reoccur and how soon after the restore?

Again, from all I've read and done so far, it doesn't seem that there is a solution other than having the iMac replaced. Which, if this problem is as widespread and documented as it sounds, is a big problem for Apple. I originally shelled out the money to buy this because of Apple's reputation for creating a product that functioned properly and lasted for well more than 3 years. I'm not at all happy to read some 32 pages of problems dating back to 2010 and see that Apple has no solution for the problem (other than, replace your iMac with a shiny new one!). We had a PowerBook G3 that ran great for 9 years (into it's 3rd owner) before it was destroyed by said owner and a PowerBook G4 that's still kicking after 9 years without a problem. However, it does seem (as others have mentioned) that Apple's attention on non-computer products has made the quality of their computers suffer over the last 4 - 5 years. It will make me think twice if/when I have to replace a 3-yr old iMac.

Hello,

I think I have found the sliver bullet to fix our problem. I bought a 27in 2010 i3 iMac on Ebay. It only had 4GB of RAM, and I was looking forward to upgrading to 16GB. Before the iMac arrived I went on Amazon and bought 2X 8GB sticks of Consair Ram with the correct specs for my iMac. When the iMac arrived, I changed the ram right away. I know it wasn't smart, but I was excited. I turned on the iMac and it started crashing right away. The only way for it to work properly was to use the 4GB of OEM Samsung RAM it came with.

I did some research and found that this a common problem. I never had a problem like this with any of my PC's. One day I pulled out the RAM and I started to wonder if I could buy the same OEM Samsung RAM. Turns out you can buy the OEM Samsung Ram and other OEM brands for iMac's. I found OEMPCWorld.com. I was able to search for my model of iMac (MC510LL/A) and, I ordered 2X 2GB PC3-10600 (1333Mhz) 204 pin DDR3 SODIMM RAM for $23.70. I couldn't belive the price.

I recived my RAM yesterday and it's the same OEM Samsung RAM that came with my iMac. Today I installed the RAM for a total 8GB of RAM. I opened up Photoshop and other apps with no crashes. I left my iMac on a total of 10 hours and counting and still no crashes. I plan to order more RAM to see what happens.

That is what solved it for me. Core i7, purchased Feb 2010 [late 2009 model]. Ran fine, no crashes with 4GB. Upgraded to Crucial 16GB spec memory. Random shutdowns/reboots for 6+ months. Moved to Samsung 16GB memory, no shutdowns/reboots in over a year [not one since moving to Samsung memory!]. I don't like what Samsung has done in the iPhone patent case, but I will say this - their memory works perfectly fine on my iMac.

I have an iMac 21,5" Core i5 2.7 GHz with 4 GB of Samsung RAM.

And this iMac suddenly shuts off without warning. And i could wait from 3 hours to several weeks when he powers on again. Really odd.

I have ben experiencing this problem with my 24" iMac Intel for about six months now and I may have some insight into my problem, if not others'. About a year ago, my Sony Bravia began shutting down by itself for no reason, but it would turn back on when I pressed the remote power button. When the iMac started doing it, I had to unplug it for at least 15 minutes to get it to reboot. Sometimes it would stay on up to 24 hours, other times it would start powering off after a few minutes, no matter what program I was using.

The Sony and the Mac are on the same circuit.

I took it in to Apple three times and they could never reproduce the problem. I took it to my office and it worked fine for two days. Back home, it worked for 36 hours and then started acting up again.

What I know about my house is that the wiring is funky. A tree fell and dislodged my power drop -- not disconnected, but it sags now. I also have a couple of wonky power outlets, one of which was feeding my computer power. I'm going to have an electrician look at the power flow, but I'm fairly sure that's where the problem is coming from. A combination of bad power (highs/lows, surges, grounds, whatever) and a particularly sensitive power supply on the mac. My other, older macs have no problem whatsoever. But seeing that the Sony and the Mac share similiar power supply sources (I would bet), are having the same problem, I would look closely at your power feeds. I'll let you know what I find out.

Jay Gamel

So I'm not even sure if my problem is the same as the ret of you, mine seems more severe.

I bought a used 27" i5 w/16gb of Samsung. Was working great and then I noticed it was off. Powered up, shut off a few mins later, then it stopped turning on all together. If I unplug it for a few hours, I'm able to boot to the apple logo and sometimes see the desktop, but it won't stay on.

I have torn the computer apart (no warranty) several times, even taking out the CPU and reapplying thermal paste. No dice. I replaced the logic board and still nothing. I know a dead logic board won't boot at all. I feel like this is a power issue. I don't knowif I can call or bring it to the Genius Bar because of how many times I have torn it apart. No idea.

Anyone hear of this?

Has there been a any real resolution around this one ... I can't seemt to pick up a clear solution from all the posts.

I have a similar problem: Mid 2011, 27" i5 on Lion 10.8.2. I through the machine would restart randomly, so did the uals stuff mentioned here:

• SMC reset
• Spotlight cache (completeley removed indexing for now)
• Swapped out the 32G of OWC ram for the original 2x4G it came with
• Re-installed 10.8.2

Nothing seemed to work. Then I noticed that reboot either happened when I was away, or when I tried to login. Somtimes twice - when I re-login after a power-cycle ... it seemed to be a wake from sleep issue. I'm guessing a power managemet problem.

I've turned off the sleep options in teh power manegement, just the screen goes blank, don't stop disks or "sleep". For the last day no reboots.

Any ideas ... this is a really bad work-around. Also, I'm not getting any panic or crash reports when the system reboots.

Any ideas/help most welcome. At my wits end on this one.

Thanks

Two things to try: Get a good quality battery backup/surge protector, and hook the iMac up to it [and have the UPS hooked to the exact same outlet that the iMac was hooked up to].

The 2nd thing - a bit cheaper, but maybe less practical - find an outlet in the house/office that is not on the same circut as the outlet you are currently using, and plug the iMac into it [putting back your energy savings preferences the way they were beforehand, so you can tell if it makes a difference].

Since the times your iMac has issues are when you are doing something to wake the system, I suspect the extra load of starting the drives/screen is causing a problem with your home's electrical system [eg: i have all my computers, etc, on UPSes and when certain big things happen, like the heater comes on, or central air comes on, some of the computer go onto battery backup for a 1/2 second - bad wiring, even though the place is new; others in the area have the same issue].

Something to try... :\

After lugging my iMac four times to the Apple store, they finally replaced the power supply. That was 10 days ago and so far, so good. I'm not taking any bets, however.

2.7 imac i5, 10.8.3

what a nightmare. first they wipe and replace, (restoring Adobe CS ultimately cost $100 and another two-day nightmare with adobe greed and paranoia/fear and loathing), then schedule power supply and Circuit board replacement but stop when I discover a mouse-gnawed power cord (which was NOT the problem), then they keep it for 48 hours and it doesn't crash and take it back home (where it promptly crashes again, another $100 to have my electrical system checked by a contractor), and the fourth time I get a power supply. It's a 15 mile drive to the store.

Apple knows what this problem is and does not want to make a recall. I have no idea what they are thinking about all that cash laying around -- in spite of the stock tanking -- but they're going to have to shell out on this one eventually. Hopefully before there are 64 pages of people going crazy on this forum.

I do admire the Apple Store Geniuses for managing to keep a straight face when they tell you, "We can't find anything wrong with this machine ..." or 'Hmm, that's a new one."

As for "Things to Try," I tried them all. You might as well stand on one leg and scratch the cat while you boot up, just as effective. This is a random problem in the power supply.

It's a defective hard drive people. Do your homework.

Re 27 inch random shut down

Today is the fourth day after I have setup a brand new IMac 27 inch i7 with 32GB and it reboots more times in a day than my 2009 Macbook Pro 17 has done in 4 years! 4 times by 3 oclock this afternoon. It seems to be random, yet there maybe a relationship with the network either wired or through the ethernet, however it certainly is not any complex task.

I shall investigate further, if there any ideas of solutions please let me know as I am several hours drive away from an Apple service centre.