I think I may have found a bug with Windows 7 (professional in my case) which deals with power management. In my power settings I have that Windows 7 will hibernate if my battery gets to a 'critical' level. If I drain my battery until this auto-hibernate happens then plug my power cord into the laptop (could be hours later) and power it back up, Windows 7 will resume and ask me for my login and immediately initiate a Shutdown after a successful login.

  1. Can anybody else confirm this behavior?
  2. Would you consider it a bug?
  3. Any way to prevent this shutdown?

I had the same problem, found the solution at http://helpdeskgeek.com/windows-7/windows-7-computer-shuts-down-when-waking-from-sleep/

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  • Thanks so much for pointing this out. Glad to see this is being seen as a bug and somebody dug out a fix for it. – SiegeX Dec 14 '09 at 7:10
  • For the record (since the page has disappeared from the web and might someday disappear from the Wayback Machine), the solution is to delete HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Power\SystemPowerPolicy and reboot. It also says they were able to reproduce the problem by changing the critical battery action from Do nothing to Shut down (and saving that setting) and then changing it back to Do nothing. This does look like a Windows bug. As of late 2015 it's still not fixed, and this solution worked for me. – benrg Nov 13 '15 at 4:09
  1. No.

  2. No. I'd consider it a safety mechanism. You'll probably find there's a polling service on the battery monitor that fires every few seconds or something, and it decided not to risk waiting that period (I am guessing here).

  3. Don't drain the battery that much before plugging in power.

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  • Just to clear up some facts, as soon as Windows 7 forces my laptop into hibernate I then close the laptop and let it sit in that state for a few hours. When I get back from work the following day I'll plug the laptop in first then power it up and then it does an auto shutdown. When I immediately power the laptop back on again, everything is as normal. – SiegeX Nov 24 '09 at 9:11
  • Yup, that's how I imagined it when you first commented. The point is, in hibernate, the laptop is off. You can take out the battery, remove the power, whatever, and it won't be affected. As for plugging it in before turning it on, my answer still stands - (I think) Windows only polls the battery monitor at regular intervals, and if it's already in critical mode, it's just turning off as a precaution. Personally, I'd avoid letting it go into critical mode before plugging it in. – user3463 Nov 24 '09 at 11:04

I had the same problem. Again.

I tried changing the power plan, creating a new one, reinstalling the UPS, etc, etc. But the thing is Windows won't let you change the values of "Low battery level" and "Critical battery level" no matter what you do.

I found out is something related with permissions in the registry. For some reason, they get screwed up. This is what I did to fix it. I don't take any responsability, of course. ;)

  1. Go to HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Power\User\PowerSchemes
  2. Edit the permissions for HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Power\User\PowerSchemes. Go to Advanced -> Owner, and check "Replace owner on subcontainers and objects". Click ok.
  3. Go to Advanced again, check "Replace all child object permissions with inheritable permissions from this object". Click ok.
  4. Now you should be able to change the values without problem from Power Options.


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