Mac Pro randomly shuts off. Can turn back on, but only starts up intermittently.

Discussion in 'Mac Pro' started by portraitofamac, Aug 6, 2011.

  1. portraitofamac macrumors newbie

    Aug 6, 2011
    Hi guys. I'm new here. Need help.

    A few days ago my Mac Pro randomly turned off. I was able to turn it back on, but it wouldn't start up (the power light comes on, but nothing else seems to happen).

    I stared blankly at my computer, with the power on and nothing else happening. About half an hour later, suddenly the "Apple chime" sound hit, and it started up! Maybe 15 minutes later (give or take) it shut off, and once again it would turn on, but wouldn't start up.

    I left it off overnight. Next day, it turned on and started up. With OSX running, I made sure to check the hard drive using Disk Utility to verify the disk. No problems. But after running it for 1.5-2 hours it shut off again. Same thing -- it turned on, but wouldn't start up.

    Just turned it on now. It turns on and starts up. Verified the disk again (OK). But I don't want to risk making the problem worse, if it should randomly shut down again.

    It's an Intel Mac Pro, 8 Core, running OSX 10.6. Bought it used, and I think it's a 2007 or 2008 model.
  2. Dadioh macrumors 65816


    Feb 3, 2010
    Canada Eh?
    Possibly thermal issues? Do you have something like iStat Menus installed so you can monitor temps? If not, install it and report back all your temps.
  3. Thermonuclear macrumors 6502

    May 23, 2009
    For problems like this..

    For problems like this, the first thing to try is to examine the last entries in the system log file. Other than a catastrophic fault, the shutdown and its reason are always logged.
  4. schulmaster macrumors member

    Aug 7, 2010
    Sounds like a bad HDD. No system diagnostic failiure LEDs, and a successful boot at random after 15min?
  5. wafl iron macrumors regular

    Nov 16, 2007
    my macpro3,1 was doing this several times a day after i installed lion. Did all hardware tests you could think of, nothing came back.

    So i opened up thje computer, gave it a good cleaning with compressed air, cleaned out the 5870's fan. reseated the gpu, cleaned the memory modules and reseated each one and reseated the memory risers.

    Havnt seen it randomly shutdown since i did that (2 weeks ago almost)

    give your mac a good cleaning before you do anything else.
  6. portraitofamac thread starter macrumors newbie

    Aug 6, 2011
    I'm trying to get to the bottom of this.

    SYSTEM LOG: I checked the system.log, and when I successfully start-up after it randomly shuts off, there is a log entry for "improper shutdown detected". I'm having trouble ascertaining what the improper shutdown was. The last few events before the new start-up are definitely not consistent. In some instances (and I'm not 100% about this) it doesn't look like it logged any events before the improper shut down (but I can't know for sure without remembering exactly what time it shut down).

    Yesterday, I ran my system until it crashed again, and the last event logged in the console was my digital audio workstation trying to eject the C, and saying "no ejectable CD media found".

    TEMPERATURES: I used iStat Menus to monitor the system yesterday. I focused on the temperatures. I was able to run my system for a good hour and a half before it crashed. The temperature climbed to 50+ degrees (see attached files). The first file shows the first 30 minutes, with no real programs running. The second and third attachment show 15 minutes and 30 minutes of running my digital audio workstation.

    After that, I got distracted. I had my digital audio workstation open, but had a basically empty file open, and it was completely idle. After about 20-25 minutes like this, the computer crashed seemingly for no reason.

    I wasn't able to fully start my system up until this morning. (Every few hours, I would try to start up. But when the computer turned on, it usually would not start up, and occasionally played the apple chime and showed the grey load up screen before crashing again.)

    My best summary:

    - Haven't tried giving it a proper cleaning. But going to buy some compressed air now.

    - There's no obvious consistent problem in the system log.

    - Every time I reboot, I'm able to verify the disk. Mind you, I have four HDs running in a RAID configuration.

    - The temperatures are high. But not that high? (Take a look.) The last two images show basically the same temperatures, and 20-25 minutes after the last image the system finally crashed.

    Attached Files:

  7. JavaTheHut macrumors 6502


    Aug 15, 2010
    I agree with schulmaster Sounds like a bad HDD in your raid, what config are you running 0, 1, 1+0 is it SOFTWARE or HARDWARE?
    Boot from your back up and use disk utility to verify the raid, this would imply that you have external bootable backup or boot from a HDD/SSD in the Optical bay if all your HDD are in the sledded bays. you may need to make the RAID disks function multiple times if only one HDD is intermittently bad you will need to flush it out. Then once it fails you may then identify the disk Connection ID: "Bay *"
  8. portraitofamac thread starter macrumors newbie

    Aug 6, 2011
    I thought I'd give everyone an update and a huge thank you.

    I've been running my mac pro with the case off, an a huge room-fan sitting right beside it blowing directly in. I've run the system for at least an hour or two longer than before. No crashes or spontaneous shut-offs yet. I suspect this confirms it's a temperature thing.
  9. Dadioh macrumors 65816


    Feb 3, 2010
    Canada Eh?
    Your memory and your northbridge look quite hot. For comparison I am doing a handbrake run right now (max loaded) and my FBDIMM Risers and VRM are in the 40's. My Northbridge is at 63. That is my ambient air at 24 and you are at 31 but still that is only 7deg difference.

    Does your memory have the approved apple heatsinks?

    Now I am on a Mac Pro 1,1 and you say yours is a 2007 or 2008 model? Can you verify the exact model?
  10. zephonic macrumors 65816


    Feb 7, 2011
    greater L.A. area
    Apologies for reviving an old thread, but it was the first one to come up when I googled my issue.

    My 2009 MacPro quad (Xeon W3520, nVidia GT120, 12GB RAM, 1x640GB HDD, 3x 1TB HDD) has been churning along fine since September 2011, but in the last week it has randomly restarted twice, the second time being about 30 minutes ago.

    At first I thought it was brief power outages, until I realized that none of my other equipment did this. I have included the system log below, and would like to ask the boffins here what it all means. Is iStats Menu somehow repsonsible? Or was it Firefox?

  11. bebop666 macrumors newbie

    May 16, 2014
    macbook pro reboots

    funny that for what is refereed to as a hardware problem is so prevalent. My macbook pro also started rebooting on its own after upgrading the operating system. I suspect its because the new operating system is so massive that your RAM starved machines are having a nervous breakdown. I upgraded to 4gb. No problems since. But, is it my imagination or is the machine running hotter?

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