Question Why does my PC soft reboot?

[Craig234]

Sometimes overnight the PC 'soft reboots'. It goes to a screen saver, needing a password to be entered, after which things like any running programs are closed, but it hasn't closed all my Chrome tabs like a reboot usually does. It doesn't go through a normal boot, it's up fast. It's a bit annoying when I had open notepad documents or things running.

 

[VirtualLarry]

Sounds like a Sleep Mode problem. Do you have your PC set to "Sleep after X Minutes? If power gets cut to the PC or RAM, when power is restored, it will power-up again, POST, and then re-load the Hiberfil.sys (Hibernation file), and then you'll be at a resumed desktop, and have to type in your password, AFAIK.

Might want to look into this more. It could be a driver issue, or you could be having power problems, or your PSU could be failing. (Sometimes the +5Vsb which powers the RAM during Sleep Mode, will degrade or fail, thus causing problems with sleep mode, and booting.)

If you've got money to throw at the problem, could try a new fresh PSU, and see if the problem goes away.

Another, more reasoned approach, would be to investigate the software environment first, like doing a "Pwrconfig -showwake" or something like that. (Web-search it.) There's a way to show Sleep triggers and wake timers that apps and drivers have set.

Edit: If you DO decide to throw money at the problem, and try another PSU, check out Hot Deals for a $15 off $60 online purchase coupon at Staples that expires the 24th of April, 2020. They still have a few PSUs showing on their site. Most are sold out. Or just check Newegg / Amazon, I guess.

 

[Craig234]

It doesn't seem like a hardware problem like the type that would cause an actual power fluctuation, because it's not a full reboot or poweoff; and the PS is new, I got it earlier this year. It doesn't seem like a straightforward sleep setting because it happens occasionally and inconsistently. Thanks for the ideas.

 

[VirtualLarry]

Can you check Reliability Monitor for me?

Possibly, your PC is restarting during "inactive hours" (at night / over-night), to apply Windows Updates, and then Restarting. Newest Win10 1909, maybe 1903 did it too, some applications would automagically get re-started after a system Restart.

If you can pin down on what day(s) this happened on, or next time it happens, check Reliability Monitor, and possibly System Event Log, and check for Windows Updates that were applied, and if the system was Restarted.

Edit: And if the PSU is new within the last year, I would scratch buying yet another new one off of the list. That's probably not the issue. (It could have been, had it been 5-10 years old, but I'm guessing off-hand that this is a Windows Update / Restart software issue.)

 

[Craig234]

You might have nailed it. Thanks. I never heard of reliability monitor. There was an update last night, though around 5PM so that doesn't quite match but close. There are 'application failures' and warnings nearly every day (not always the same day).