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imac shutting down unexpectedly

35033 Views 57 Replies Latest reply: Apr 3, 2014 4:14 AM by patmos77 RSS
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23degreesN Calculating status...
Currently Being Moderated
Oct 13, 2010 7:18 AM
iMac shuts down at random and seems to be attributed to invalid volume file count. I managed to successfully repair the disk and permissions through 'Utilities' on the Installation CD but problem reoccurs - after each unexpected shutdown Disk Utility reports another invalid volume file count.

Typing 'shutdown cause' in the all messages filter of Console reports no result - its like it never happened!

So far it has shutdown 10/12 times today, although the last shutdown was the longest interval yet: an hour or so.

iStats show CPU temperatures as fairly normal:

CPU 52
CPU Heatsink 46
Ambient 26
Mem 49
CPU Diode 60

any thoughts?
iMac, Mac OS X (10.5.8)
  • den.thed Level 7 Level 7 (23,385 points)
    Currently Being Moderated
    Oct 13, 2010 9:50 AM (in response to 23degreesN)
    Hi 23dedreesN

    Welcome to Apple Support Communities

    Check for loose electrical connections and reset or replace that surge protector if it's old.

    Run the Apple Hardware Test > http://support.apple.com/kb/HT1509

    Dennis
    Early Core Duo - 320GB WD Caviar Blue HDD - 2GB RAM - 21.5 LG Display - iPad -, Mac OS X (10.6.4), - Maxtor FireWire HD's - WD Passport - Nikon - Epson - 80GB Classic - 2GB Nano
  • den.thed Level 7 Level 7 (23,385 points)
    Currently Being Moderated
    Oct 13, 2010 11:54 AM (in response to 23degreesN)
    When you say "shutting down unexpectedly" do you mean that everything just going black or that you are having Kernel Panic's? > http://support.apple.com/kb/HT1392

    If Kernel Panic, see > http://www.thexlab.com/faqs/kernelpanics.html

    Also note: that in 10.5 Leopard the Disk Utility's Repair Disk Permissions messages that you are getting can be safely ignored. > http://support.apple.com/kb/TS1448
    Early Core Duo - 320GB WD Caviar Blue HDD - 2GB RAM - 21.5 LG Display - iPad -, Mac OS X (10.6.4), - Maxtor FireWire HD's - WD Passport - Nikon - Epson - 80GB Classic - 2GB Nano
  • den.thed Level 7 Level 7 (23,385 points)
    Currently Being Moderated
    Oct 13, 2010 12:50 PM (in response to 23degreesN)
    Could be a loose/improperly seated or bad RAM module.

    Reinstall the RAM, pushing firmly on each module with both thumbs to ensure they are fully seated.
    Reinstall your factory RAM if you have upgraded with third party RAM.
    If you have 2 modules, install one module a time and test.

    See > http://support.apple.com/kb/ht1423

    It could also be an overheating problem with any number of components, that is causing the iMac to shut down abruptly. If the Extended Apple Hardware Test does not catch the problem, then you will need to take it to an Authorized Service Provider for testing.
    Early Core Duo - 320GB WD Caviar Blue HDD - 2GB RAM - 21.5 LG Display - iPad -, Mac OS X (10.6.4), - Maxtor FireWire HD's - WD Passport - Nikon - Epson - 80GB Classic - 2GB Nano
  • elmac Level 5 Level 5 (4,230 points)
    Currently Being Moderated
    Oct 13, 2010 1:29 PM (in response to 23degreesN)
    Hi, are you using a Surge Protector?
    Have you tried the Mac on a different power circuit?
    Try a different power cord!
    Have you downloaded any New Apps just prior to this Issue?...L
    5Macs - 2iPhones - AppleTV - 7iPods - 3Leica's - 2Nikon's, Mac OS X (10.6.4), Use em all" - Luv em All" - Need em all!!
  • .frustration. Calculating status...
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    Oct 15, 2010 12:00 AM (in response to 23degreesN)
    Hi,

    I am experiencing almost exactly the same problem as 23degreesN. When the computer is idle it will remain powered on but when applications are running (and it doesn't seem to be attributed to a particular application) it will randomly shut down with black screen and has to be manually restarted (although like some other posts it will always start straight away without problem)

    In my energy saver settings I have 'Restart automatically after a power failure' unchecked which is probably why it doesn't automatically restart.

    To try and resolve the problem I have done all that 23degreesN has done, I have also done a few things in addition:

    I have used Diskwarrior (which was run from an external bootable hard-drive) to try and repair the computer. It completed the repairs successfully but the problem still remains.

    I swapped the power cable from another iMac hoping that it might have been something as simple as a faulty cable. problem still remains.

    Anyone out there with any ideas?
    imac 24", Mac OS X (10.5.8)
  • .frustration. Level 1 Level 1 (0 points)
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    Oct 15, 2010 3:37 AM (in response to .frustration.)
    continuing from my post above....

    I have tried taking out the RAM, putting one back in, restarting - computer shuts down after 5 mins
    and then replacing it with the other stick assuming that one may be faulty - again computer shuts down. Conclusion: I dont think the RAM is the problem unless both sticks are faulty

    The only thing I can think of now is that the power pack in the computer is faulty but I am doubtful that this is the cause because if the computer remains idle (no applications running) it doesn't shutdown.
    imac 24", Mac OS X (10.5.8)
  • bressst Calculating status...
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    Oct 15, 2010 2:57 PM (in response to 23degreesN)
    Ok let me give you my thoughts after all the shutdowns I had on 2 iMacs 27:
    I got my iMac 27 2.93 early september 2010. I made the upgrade to 16Gb (not have anytime to test the original 2x2 GB). I got many shutdowns. I call the support and made on my own all the following tests before calling them :
    1 - Run the Techtool deluxe from Apple : everything was ok
    2 - Reset the RAM : problem still there
    3 - Reset SMC : problem still there
    4 - Reinstall the OS from scratch on the internal 2nd drive (HDD instead of the SDD) : problem still there
    5 - Deconnect all peripherals connected to the iMac : problem still there

    It took 5 minutes to the Apple support to understand it was probably a hardware issue with the motherboard or an electrical issue. As it was less than 15 days I bought the mac, they send me a new one and got the old one after I received the new one (good service).

    UNFORTUNATELY SAME ISSUES with the new one !!!!
    Redo the same tests and same problems.
    So I'm not sure about the interest for me to get a third delivery...
    Reading all the threads, I conclude this is either a real hardware issue or a RAM issue because of the 16GB.
    I just decreased the RAM to 12 GB yesterday and I will see....I'm pretty sure the problem will not occur. If confirmed I think we have no other choice to wait for an update unless the problem is a real hardware issue. I bought the apple care program so I can see within the next 3 years.
    This is crazy not being able to use the 16 GB.
    Feel free to give your thoughts.
    Thanks
    iMac 27 - Mid 2010, SSD + HDD - 16 GB
  • bressst Level 1 Level 1 (0 points)
    Currently Being Moderated
    Oct 19, 2010 3:17 PM (in response to bressst)
    So far no shutdown after 4 days....
    iMac 27 i7 2.93Mhz - iMid 2010, Mac OS X (10.6.4), SSD + HDD - 16 GB (12 now)
  • emilvals Calculating status...
    Currently Being Moderated
    Oct 22, 2010 2:19 AM (in response to bressst)
    Hello, I bought a new 27" iMac i7 last week. First problem I encountered and I am still encountering is random packetloss, I'm using a wired connection.

    I also bought 16GB Ram from Macsales.com this week and installed it in the machine and this morning my iMac just completely shutdown like you are experiencing. Hardware diagnostics don't find any problems.
    27" iMac i7, 16GB Ram
  • bressst Level 1 Level 1 (0 points)
    Currently Being Moderated
    Oct 23, 2010 4:54 AM (in response to emilvals)
    Hello,
    This has been now 8 days with 12 gb instead of 16 gb, still no shutdown (for information my iMac is on 24 by 7).
    So it seems that the 16gb is causing the problem....and we all have different brands of RAM.
    I'm not sure if someone bought the 16gb directly from Apple to see if they have the problem or not.
    If YES, I would say there is a serious problem on the Apple side
    if NO, then they are using very specific RAM (not standard) and this is not acceptable
    iMac 27 - Mid 2010, SSD + HDD - 16 GB
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