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I just experienced a random shutdown today with my 27" iMac and it was really hard to get it to start back up. I just purchased it in August 2010. It's a totally stock setup...2.8 GHz i5, 4 GB RAM, 1333 MHz DDR 3. I changed out my surge protector a few days ago. I went from an APS w/ battery backup to a Belkin surge protector w/o battery backup. I don't know if the new surge protector would have anything to do with it.
Hi. On Monday last week I ordered a refurb 27 inch iMac i3. Stock spec, £200 off list price.
Within an hour of opening it and migrating my stuff the screen went white while trying out new X-Plane settings and I had to reboot. Then I had two kernel panics. I put it down to maybe being a new OS instal. Maybe it was updating itself or something...
Next day it had two more. Then it wouldn't wake from sleep, forcing me to hard re-boot. This happened twice. I closed the machine down and left it.
The next morning I booted the machine and it immediately had a kernel panic. Later when I booted the machine the screen flickered. I ran tech tool deluxe: it showed up a VRAM problem.
I phoned Apple and told them I wanted to replace it but they said that their policy is only to give refunds on refurb units.
I have since read lots of threads about kernel panics on newer Macs following use of migration assistant, and of 27-inchers refusing to wake.
I tried reinstalling OS X just to see if it was something I'd migrated. It seemed stable for a while and I thought I might just have to migrate my stuff manually. I ran Tech Tool Deluxe again out of curiosity and it showed up a directory failure. Then it had another kernel panic.
So back it's going.
They offered me a goodwill gesture, but I'm disappointed, and the things I've read about 27-inchers make me wary of buying another one. (X-Plane looked fantastic when it was running, though...!)
For the time being I think I'll leave it and buy again when some of the issues have been addressed, probably from my local Apple store.
What I have been thinking of lately is why this problem only on an iMac?
I checked the forums of the MBP and Mac Pro. They appear not to have the exact same shutdown problems . Some kernel panics or frozen screens but not like here with the iMac.
The Mac Pro (single processor) is using up to max 16 GB of ECC sdram in 4 slots, see below.
2.8GHz and 3.2GHz systems: 1066MHz DDR3 ECC SDRAM
3.33GHz system: 1333MHz DDR3 ECC SDRAM
Four memory slots supporting up to 16GB of main memory using 1GB, 2GB, or 4GB DIMMs
Could this mean something that Apple could look into?
My new iMac is only 1 week old and it has shut down on me 7 times. The phone techs at Apple Support keep telling me to un-plug, bla, bla, bla. I thought it was me, cause I'm old "but awfully tuff". But after reading these discussions, I realized it's the iMac with the glitch. Has anyone gotten the lemons out of their iMacs ? Is this something a user has to live with? Do the apple techs know how to resolve this random shut down problem ? Can a tech fix it ? Help me out here, I have a Hubbie of 47 years that shuts down randomly, I sure don't want a computer that does the same.
As of now, the Apple techs don't know how to resolve the problem. At least, the guy looking at my iMac has absolutely no clue. I've talked to him about RAM compatibility and things discussed in this forum, but since the shutdown NEVER happens when it is in the repair shop, he can't do anything about it. I've made sure it's not my house or me: I've had an electrician come in and check the power outlet and wiring; and I am a Mac user for 20 years.
I do suggest taking your computer in for the Apple tech to look at, just to make sure it isn't the power supply unit or logic board failure. The home remedy that seems to work for a lot of people is to change the RAM to high grade ones manufactured by Samsung or other reputable companies.
my imac 27 (2009), i7, 8GB Ram freezes every couple of days during sleep with a black screen or during wake up (mac os 10.6.5).
only solution is to press the power button.
i have no other bluetooth device than apple trackpad, mouse an keyboard.
no usb hub just one canon printer connected via usb. nothing else.
this is really annoying.
Looks like the same symptoms. But from a different (earlier) type of iMac.
Judging from the 2009 you probably have this iMac for a year maybe longer?
Is this the first time you have these problems? If so the cause might not be the ram.
Do all the tests and tricks described in several threads/posts of this forum, like AppleHardware, Render
from OWC, Pram etc.
Look at this site : http://www.thexlab.com/book/troubleshootingmacosx.html
It says for Macbooks, but you can use it for iMac as well.
Same thing happening since my 27 inch Intel Core i7 was purchased in October for graphic design work. It shuts down while it's idling and then to restart it I have to unplug the power cord from the surge protector, wait a few seconds, then plug it back in. I've spent plenty of time on the phone with apple care, done all the same stuff we've all tried, then I hauled the gigantic thing onto the subway to bring it to the Apple store. Of course, like others have experienced, the technicians weren't able to reproduce the problem, and sent me on my way with a new power cord. It's still happening just about every time I let it go to sleep for a while. Today I argued for a replacement as I have wasted so much time dealing with this problem and very little time using it for graphic design. Despite having all my troubles, they're reluctant to replace the computer, and their best offer was to send someone to repair it at my home in a few days. I'm so frustrated. Any suggestions on how to skip all this b.s and convince them to just send me a replacement or refund my money?