[Laurence]

I've heard about the MacBook users experiencing the "Random Shutdown Syndrome" (RSS) alot, however I can't seem to find anyone having this issue on an iMac. I have an iMac 17" (Core Duo model, not Core 2 Duo) and about once a month I'll be typing, reading, etc and all of a sudden the screen goes black and I think I've hit the screensaver shortcut or something, but by the time I reach for the mouse I hear the startup chimes and the computer is rebooting... It just happened a few minutes ago so I thought I'd post and see if anyone else has been experiencing this. Here is the output from the system.log for the time when it occurred. I see nothing unusual, but maybe someone else may have some idea.

May 17 03:15:04 Cathys-iMac cp: error processing extended attributes: Operation not permitted
May 17 10:26:33 Cathys-iMac kernel[0]: IOAudioStream[0x2b81300]::clipIfNecessary() - Error: attempting to clip to a position more than one buffer ahead of last clip position (1befc2,3d1c)->(1befc4,3594).
May 17 10:26:33 Cathys-iMac kernel[0]: IOAudioStream[0x2b81300]::clipIfNecessary() - adjusting clipped position to (1befc3,3d1c)
May 17 11:50:11 Cathys-iMac sudo: lhawkins : TTY=ttyp4 ; PWD=/Users/lhawkins/Desktop/lft-3.0 ; USER=root ; COMMAND=/usr/bin/make install

Shutdown occurred here... 14:09:xx

May 17 14:09:37 localhost kernel[0]: hi mem tramps at 0xffe00000
May 17 14:09:38 localhost kernel[0]: PAE enabled
May 17 14:09:38 localhost kernel[0]: standard timeslicing quantum is 10000 us
May 17 14:09:38 localhost kernel[0]: vm_page_bootstrap: 251954 free pages
May 17 14:09:38 localhost kernel[0]: mig_table_max_displ = 71
May 17 14:09:38 localhost kernel[0]: Enabling XMM register save/restore and SSE/SSE2 opcodes
May 17 14:09:38 localhost kernel[0]: ACPI CA 20060421
May 17 14:09:38 localhost kernel[0]: AppleIntelCPUPowerManagement: ready
May 17 14:09:38 localhost kernel[0]: AppleACPICPU: ProcessorApicId=0 LocalApicId=0 Enabled
May 17 14:09:38 localhost kernel[0]: AppleACPICPU: ProcessorApicId=1 LocalApicId=1 Enabled
May 17 14:09:38 localhost kernel[0]: Copyright (c) 1982, 1986, 1989, 1991, 1993
May 17 14:09:38 localhost kernel[0]: The Regents of the University of California. All rights reserved.
May 17 14:09:38 localhost kernel[0]: using 5242 buffer headers and 4096 cluster IO buffer headers
May 17 14:09:38 localhost kernel[0]: Enabling XMM register save/restore and SSE/SSE2 opcodes
May 17 14:09:38 localhost kernel[0]: Started CPU 01

farther down in the startup sequence I see this line...

May 17 14:09:38 localhost kernel[0]: Previous Shutdown Cause: 0

Is the zero the "unknown cause" or does it mean something else?

I called Apple support and they said that I would have to take it in to an Apple Store to have it looked at, but if it was found to be a software issue I would be charged for the troubleshooting. If it turned out to be hardware it would be free. (The computer is almost a year old) I guess I could just buy the AppleCare for $169 and then I'd have two more years to figure it out.

[bearcatrp]

Did you recently install ram? You should boot from your install disk, verify disk,verify permissions. If ok, if you don't leave your mac on all night, run the maintanance with a program call macjanitor, or others that are out there. You might want to run the hardware test while you have the install disk booted up too. If all comes back good, take it in.
Randy

[Big Mac]

Buy AppleCare.

[ph0ust]

how strange. i have a 17" g4 imac and just had my first kernel panic about 30 minutes ago. happened when i put a cd into the tray and the tray closed. so far so good after restart, but i hear that it is symptomatic of something significant and likely to occur again.

[Veltliner]

This may be very off, but have you tried to check your software with DiscWarrior 4.0?

It repairs problems in the directory.

Good luck!

[Laurence]

RAM is at 1GB and has been since purchase. Nothing has changed inside the iMac. It was happening about once a month when booted up of the internal HD. About a month ago I started booting up off an external FW drive. It was fine up until today. Then it shut down for no reason. Since the same behavior has been experienced when booted up off two separate drives I doubt its a software issue, but just in case I'm formatting the internal drive now and I'm going to reinstall the OS on the internal drive. I guess I'll bite the bullet and just buy the 2 years of Applecare now and if it does it again from the newly formatted internal drive I'll take it in to the nearest Apple Store. The strange thing is that it doesn't happen when its hot or under heavy use or anything which makes me think it has to be something completely different than the standard MacBook random shutdown issue. Oh, well. As long as others aren't experiencing similar issues I'll assume its just a bad solder joint on the motherboard and not a defect of design.

[kcmac]

Our G5 imac has started to randomly shut down. Sometimes, we have to wait awhile before we can turn it back on. Anyone with any ideas?

[P]

Originally Posted by kcmac 

Our G5 imac has started to randomly shut down. Sometimes, we have to wait awhile before we can turn it back on. Anyone with any ideas?

Sounds like overheating - either the CPU is a bad batch, or you've blown a capacitor on either the motherboard or in the power supply. My bet is the latter, but in either case, it's nothing you can fix yourself. Contact Apple.

[kcmac]

Took my iMac into the KC Apple Store tonight on the Plaza. No questions asked, they just fixed it on the spot! 45 minutes later and I was on my way home with a newly installed power supply!

I bought my iMac in September of 2004. Don't have Applecare. My serial number did qualify for the extended warranty for the Power and Video issue. But they never even asked about it.

This is exactly why I buy from high quality companies like Apple. And the crew in KC couldn't be any nicer.

BTW. Made a few calls with an iPhone and gave it a good go. Barely escaped without buying one.

[asodamiac]

I had the random shut down happen to me (brand new, April release iMac) once with Leopard 10.5.2. Thought it was a fluke so I let it go. Upgraded to 10.5.3 and I just had my iMac shut down on me today.

Is this again just a fluke or is this something I should have Apple take a look at?

Edit: Also, is it normal for my iMac to freeze while running Verify Disk? I get the spinning beach ball and everything is frozen, except iTunes keeps playing and I can move windows around but nothing else registers. If I click on buttons, everything happens very rapidly after the iMac "unfreezes."

[0157988944]

Did you read the thread? No, its not a fluke... it happened twice! Verifying Disk freeze probably isnt so bad, but for me only disk utility freezes. Take the iMac to Apple.

[asodamiac]

Ahh guess youre right. It's going to be a hassle to pack this bad boy up!

[zerock]

hasnt happened to me.

[imacnubie]

I was stoked about finally owning a quality machine. I took the plunge when I purchased an Imac model A1225 24 inch sn w8750aa7x89 machine. The kids fell in love with it and I was amazed by it. It was a demo machine and got it at discount so I felt better about that. The machine had been reloaded by the salesperson at the store.
I had no experience with any Mac product but had heard of the hype. Had I known about this power problem I would have held on to my bucks.

The machine started shutting down on its own right away but I was unable to attribute it to a design flaw. I liked how the machine looked and decided to give it a chance. I have left the machine with my family while I am away for a year and they are experiencing more shutdowns while browsing and playing on line Disney games. Thank God that I purchased the care plan before I left home.

Anyway, my machine is now at the mac retail store for repair due to said problem. If I owned a machine that most people pay premium price for I would expect it to perform as a world class product it is supposed to be. THis problem if not taken care of by Apple makes this machine an impressive overpriced piece of crap.

I hope they fix it! BTW I just happen to own some of this company's stock! So far I am not impressed.

[Veltliner]

I had a power-out twice, and each time I had to wait ten minutes before I could switch my 24" iMac back on.

[asodamiac]

Well, my iMac is currently at the apple store being repaired. I let them know about the screen gradient issue as well so they are replacing the power supply, lcd screen, and logic board.

My powerbook is DARNED slow. I can't wait to get my iMac back!

[kmkkid]

Originally Posted by asodamiac 

Well, my iMac is currently at the apple store being repaired. I let them know about the screen gradient issue as well so they are replacing the power supply, lcd screen, and logic board.

Wow, they may as well have just gave you a brand new iMac.

[asodamiac]

Hahaha serious! The repair is taking a little longer than expected too... It's been 9 days so far, so they should have it ready by tomorrow or Monday at the latest. I really can't stand using my Powerbook anymore. Even the most simplest tasks take forever!

[asodamiac]

Well I just got a call back from my Apple store and after 10 days, they said they were unable to see an issue in the LCD screen (gradient which is brighter on the bottom than the top) and couldn't "replicate" my iMac shutting down "intermittently."

So I spoke to one of their technicians and he's giving me excuses left and right and really has no idea what he's talking about at times.

Anyways, I'm wondering if other people have had issues with their repairs as well? All the technician could recommend to me was to send my iMac to an Apple authorized repair center and pay $50 dollars to have them take a look at my computer.

I must say, this upsets me a tiny bit.

Oh well.

[asodamiac]

Sorry for all the posts, but I just got the final word from the Apple store and they said they would not replace anything because the LCD is working as "normal." They tested their screens around the store and said it was similar to my own and that it was within specifications.

As for the power supply issue, they said they couldn't replicate that issue either (I told them it was intermittent and occurred every week or two) so they won't be replacing that either.

Well, I'm glad I have an external display :X

[apandy]

I purchased my IMac Sept. 2007. In October it started to shut down randomly a few times. Then it shut down and it would not start up at all. I have been using a Mac for 20 + years and have owned them for the last 9 years. I took it to the Apple store and they had to replace the mother board. They said it had burned out. Well here we are just about a year later and she just randomly shut down on me last night. I had to unplug everything here in my home office and them plug back it to get up and running. It really shocked me that tis would happen. As I said I have been using Mac for years and they have always been just strong machines. I have pushed many to their limits but this IMac may be a lemon.

[P]

There was a bad batch of electrolyte capacitors from a certain manufacturer in the Far East (I think they stole a prototype recipe from a competitor, thinking it was the final thing) that made it into many computers in the era of the first iMac G5, especially from Apple and Dell. That is what is frying, although in your case it seems that you have a much newer model.

[angelmb]

So a friend of me has this very same issue, only worse. He can't even try to solve it by booting from either the OS X install disc or the Apple Hardware Test… he can't even try any key-combo… the iMac starts up, shows the Apple logo, then the spinning circle and all of sudden it just shuts down. I guess it could be a hardware issue, either the mother board, the power supply or whatever… What could be done in before of bringing it to the Apple Service folks?

Is there any known serial # list to check if his iMac qualifies for any given extended warranty ??, we are talking about a first generation 17" intel iMac.

[angelmb]

OK, actually this is what happens to the iMac, the aforementioned MacBook issue… they blame the heatsink,

http://www.youtube.com/watch?v=iNd8Oi2Zg9g