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jrbuuck Level 1 Level 1
Over the last couple weeks my computer has suddenly and repeatedly restarted itself without warning while I was using it. It's as if the power was flipped off for a fraction of a second. I checked the power cables, of course, and they're fine. My house has good electrical and no other appliance has behaved like this.

What possible trouble could this behavior indicate? I'm making sure I've got everything backed up in case it goes down for good.


MacPro G5 (aluminum), Mac OS X (10.5.7), 2 x 3 GHz Quad Core
  • Allan Eckert Level 9 Level 9
    Hi jrbuuck;

    Is your Mac still under warranty?

    It sounds like you have a problem with either the PSU or the motherboard. I would suggest taking it in to Apple for repair.

  • Sean McCue Level 1 Level 1
    I have an 8-core Mac Pro and mine has just begun doing this spontaneous restart thing too! What the…?
  • Daniel Sparks Level 1 Level 1
    My 2006 quad did this a few days ago. Out of the blue, no warning...just rebooted on its own. I checked the temps, drives, and memory. All normal. UPS baterry backup fine,too. Diskwarrior didn't find any issues. What's up?
  • pozzlux Level 1 Level 1
    Add me to the list. My Mac Pro has been doing this for some time. It began as a problem putting the computer to sleep (it would go dark for a moment then power up again). It progressed to a problem shutting down (the machine would shut down then immediately restart). Now it spontaneously restarts, not always, but often when waking from sleep. I've done numerous Permissions repairs, run Disk Warrior, etc. The problem has even spanned my upgrade from OS 10.5 to 10.6. I have another 8-core (slightly newer) plugged into the same circuit that shows no such problems. Any ideas would be appreciated.
  • The hatter Level 9 Level 9
    Your (non-G5, these are Intel afterall, not PPCs) house may be fine, but I would still invest in a UPS for your compuer, to filter your network line, and help prevent problems like under/over that may or may not be handled by the PSU (can't hurt, and added insurance / peace of mind).

    Checked the line volts/amps/watts?
    Apple Hardware Test?
    3 hrs on memtest?
    Keeping fan rpms 300 rpm higher than stock default?
    FBDIMMs do run very very warm, enough to cause the exhaust to be able to heat a small room over course of few hours (and needs a place to go, not just against wall, or to be sitting in a cabinet which some have done).

    Maybe a neutrinio passed through!?

    I assume the system and panic logs were not able to catch anything happening.
  • Samsara Level 4 Level 4
    This is the second thread I've seen reporting this behavior. From the other I thought this had something to do with Snow Leopard but here we see different OSs involved. Pretty bizarre.
  • The hatter Level 9 Level 9
    10.5.0-.2 was very troublesome with new SyncServices that really had problems with it. The kind of thing more extensive testing (us!) uncovered.

    When watching Activity Monitor, launching Mail would start some cpu activity as a result and had to wait until it was 'quiet' before closing (I'm the type of launch and check, and then quickly close). Was taking a full minute. And closing Mail would also cause a syncservice thread.

    Installing Snow Leopard cleans out a large number (most?) of the caches,
    ~/Library/Caches/ which was where /SyncServices was I thought. It was nothing but alias-alias and the most odd set of folders.

    And that is just one 'item' that may be involved. Luckily, Disk Warrior could find and repair something that resulted from such instability.
  • Samsara Level 4 Level 4
    more extensive testing (us!) uncovered


    Yes, I'd definitely try DiskWarrior. It's strange though, when I first switched to Snow, many times the computer would try to start and then restart several times in a row before it came up. Especially when I was booting back from 10.5.8. Eventually that went away, why I don't know, but I thought at the time 10.6.1 took care of it. Now I really don't know.
  • The hatter Level 9 Level 9
    Here is one guess: that when Leo mounts a disk it touches it, and when Snow boots, it has its own unique and changed behavior. And these two cousins don't really like to talk to each other!

    I tend to pull a system. Also, remember how we had to wait after Leo for Disk Warrior to be ready? of course 10.5.0 wasn't itself ready until post 10.5.2 was out either. Disks not mounting, trouble communicating, new 'hand-shaking' going on.
  • Samsara Level 4 Level 4
    Also, remember how we had to wait after Leo for Disk Warrior to be ready?

    Yes, I certainly do. That's why I couldn't fathom the possibility that DW had been updated for SL practically on the very day it came out. Boy, did using the old version cause a mess.

    I keep thinking though, if I were in these peoples shoes I would really be upset. If DW didn't fix it, I would definitely do an erase and install and upon reboot, download 10.6.1 as the first thing to do. But not everyone has a ton of disks to back up to.
    If that didn't fix the restarts I would take the Mac in and say, "Fix it or give me another".
    Of course I can't explain why someone running 10.5.7 or 10.4.4 is having this problem too.

    What's the old saying that software can't affect hardware? Well, maybe not in terms of damage but I would think there has to be some link there. Even though this problem doesn't affect me, I really want to know what's going on to cause it. It just seems so odd.

    Hmm... I wonder why I didn't think of this before? Maybe for these users it's time to do SMC and PRAM resets. SMC seems particularly a good thing to try.
  • Samsara Level 4 Level 4
  • MindstormX Level 1 Level 1
    I started experiencing the same issues with my MAC PRO also over the last two weeks or so. It is becoming unreliable. It spontaneously reboots and I lose all that I was working on. This is very frustrating to deal with. I am reporting the same symptoms as some of the others. I have been trying to figure it out for sometime know without much progress. A common theme among these reboots is no warning of any kind, not even the gray screen of death. It seems that it is affecting different hardware configuration which may mean that it is a software related issue and since some of us reporting that is started happening about two weeks or so may add to to the theory that it could be software related.
  • blaneyart Level 1 Level 1
    Hi all, oddly enough, i thought i'd cured this problem when i switched around my 2 graphics cards and reset the SMC. The problem seemed to go away for several months this year. But just a few weeks ago it happened again, once. Then again a week later and today it has occurred twice already.

    Other than the above ideas, AppleCare technical don't seem to have much more to suggest. But in fairness to them, they have given me the opportunity to get it sorted at an AppleStore through the proper channels - this will probably be my next route - trouble is, i don't want to be without this machine.

    Sorry i can't offer any further solution, but just thought you'd like to hear a slightly different set of circumstances to the same problem. Good luck everybody.
  • The hatter Level 9 Level 9
    Dust build up inside the X1900 does need to be removed, cleaned, on a 3 month basis.

    Some people use a $29 copper cooler add-on to help.

    The Radeon X1900 otherwise will clog, overheat, and cause the system to overheat - and system fans to have to work harder.
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