Random power offs & reboots  

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  1. Posts : 355
    Win10 Ver. 1809 Build 17763.`

    Random power offs & reboots

    The PC is a fairly old custom built machine with an Asus P6T motherboard running Win 10/64 Home Build 1703. It has started powering off and rebooting itself at random times. When it does this it reboots 3 times, gets itself to the Recovery partition, and then shows the standard options that allow me to boot in Safe Mode with Networking.

    The machine seems to run OK in Safe Mode with full Network support. But of course this is not acceptable for normal use. I don't understand why it should run OK in Safe Mode but randomly power itself off in Normal Mode, but my guess is there may be something wrong with the power supply. I can replace this pretty easily, but before I do this I'd be interested in any other ideas about why the machine should be randomly powering off and rebooting itself.
      My Computer

  2. Posts : 40,588
    Win 10 Pro (22H2) (2nd PC is 22H2)

    Hi, could be your MBO... all sorts of possibilities.

    Could also be some incompatibility with installed programs, or corruption, including RAM - normal boot requires more RAM, more is running.

    You should do a RAM test, and try a clean boot for comparison.

    If it will run in Safe Mode, you could try running stress test software e.g.
    PassMark BurnInTest software - PC Reliability and Load Testing

    HeavyLoad - Free Stress Test Tool for Your PC

    If you can find a portable stress test program, you could eliminate the disk and your installed Windows and boot from Kyhi's disk (top of the Software and Apps section) and use that.

    Essentially you could remove everything bar the PSU and MBO, but you can't distinguish between them without either substitution or more test kit e.g. for the PSU.
      My Computers

  3. Posts : 355
    Win10 Ver. 1809 Build 17763.`
    Thread Starter

    Thanks, I'll try a ram test and follow up with a stress test if that runs OK.
      My Computer

  4. Posts : 414
    Win 7 Pro/32, Win 10 Pro/64/32

    The most common cause of that is RAM.
    If I were working on any PC, with the same complaint, I'd first give the insides a real good visual scan, looking for DIRT buildup on the CPU cooler, dirt on the ram sticks, and of course....bulging capacitors.

    If there are ANY bulging caps, all bets are off. You'll need a new motherboard.
    Dirt, that's evident, should be blown out. Then I'll take out the ram sticks. Examine them for dirt and then look at the brand name.
    It they are from Kingston or Spectek, replace them. Both brands are known to fail.

    I've saved ram that seems to be failing by just washing them in denatured alcohol, using an old tooth brush, to remove dirt that gets stuck between the legs on the ram chips. Dirt that you can't even see with the naked eye, can short out the ram.

    Fixing your problem is something I've done for years as a PC tech. But it can involve more than just looking at one thing.

    OH, and there can be Bulging Capacitors inside the PSU too. They show up in all sorts of electronic devices, even LCD/LED monitors.
    If you have Bulging Caps inside your PSU (power supply Unit) just replace the PSU.

    Good Luck to you!
      My Computer

  5. Posts : 40,588
    Win 10 Pro (22H2) (2nd PC is 22H2)

    Another possibility is simply overheating - thermal cut-out. Have you checked temps (e.g. Hwinfo) and CPU usage with the task manager?
      My Computers

  6. Posts : 355
    Win10 Ver. 1809 Build 17763.`
    Thread Starter

    I ran the mdsched RAM test and it found no problems. The fact that the machine boots & runs fine in Safe Mode, but not in Normal Mode, makes me think there is something loaded at normal boot time that is causing the shutdowns. I've installed Process Monitor and looked at the Event Log but not found anything (yet) that looks bad. I'm thinking about using Autoruns to stop tasks that look like they aren't necessary, but not sure how to identify those.
      My Computer

  7. Posts : 40,588
    Win 10 Pro (22H2) (2nd PC is 22H2)

    Perform a Clean Boot in Windows 10 to Troubleshoot Software Conflicts Windows 10 Performance Maintenance Tutorials
    part 1
    - how to do a basic clean boot

    Note that that leaves quite a bit more running than in Safe Mode e.g. drivers.

    You could have a look at your Reliability History (type Reli in Cortana's search bar) and, having noted the time of a crash, look at any relevant x's.

    Also check your disk - download and run Hard Disk Sentinel (trial) and post a screenshot of its GUI.
      My Computers

  8. Posts : 355
    Win10 Ver. 1809 Build 17763.`
    Thread Starter

    Yup - tried all that: no help. The system runs only in Safe Mode. HD Sentinal said C: was in "perfect" condition after running a short test. The disk is a Samsung 840-EVO and seems to have no problems.

    I've done the Clean Boot thing many times and it always reverts back to the Recovery Partition & Safe Mode. I've tried disabling all sorts of startup items using Autoruns but that doesn't help either. The System Reliability screen showed only a couple of "unscheduled" shutdowns, which is not new news.

    I did get some log files from Process Monitor, but those logs are voluminous and I was not able to find anything that looked like an error. I also checked all the Window\Logs files and found nothing useful.

    In Safe Mode I was able to make a Macrium backup OK, but it's not clear that reformatting C: and restoring that would make any difference. I still think the problem is some bug in a task loaded at boot time, but what it might be is still a mystery.
      My Computer

  9. Posts : 355
    Win10 Ver. 1809 Build 17763.`
    Thread Starter

    Some progress, but still not out of the woods:

    After one of my previous Safe Mode restarts I discovered I had no Internet connection. After comparing Services.msc with my other Win10 system I noted that many services were disabled. So I went through the list and re-enabled everything that was running on the good system. That got my Internet back so I shut the Safe Mode machine off for the night.

    This morning it booted into Normal Mode OK. So I downloaded the Prime95 stress test program and ran it a few times. Each time the system powered off after a while and then rebooted itself. I always came back in Normal Mode, which was a major improvement.

    Now I just have to digure out why the system is dropping power. The Event Log & Reliability Monitor simply say "The previous shutdown was unexpected" - not particularly helpful. I've got OpenHardwareMonitor but it doesn't seem to create a real-time log.
      My Computer

  10. Posts : 40,588
    Win 10 Pro (22H2) (2nd PC is 22H2)

    It's worth checking to see if there's a BIOS update. Given you say it's pretty old, you might be experiencing low level driver incompatibility problems, I suppose.

    See e.g.
    Unexpected Shutdown - Event Viewer Error

    (free) to see if they pick up anything, but if you've scoured the event viewer, they may not.

    Each time the system powered off after a while
    - thermal?
    - or could be any sort of glitch...

    There are other threads you can look for here on unexpected shutdown e.g.
    PC Shuts Down Unexpectedly. - Windows 10 Forums
      My Computers


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