I have a Win7 x64 system connected to the UPS. The UPS is capable of maintaining the system power for about 30 minutes. After I have connected the UPS, I have verified this by disconnecting the power cord and everything has worked as expected, I was receiving low level battery notifications and the system went off once the battery has reached the critical level. Since then a long time passed. Recently I was experiencing a power loss several times, and each time the computer went to sleep in a very short time.
I can reproduce this easily any time by disconnecting the power cord from the UPS. When I do this, the system correctly shows the battery level and the remaining battery time when I disconnect the cord (the level starts at 100% and the remaining time at 0:32 and gradually goes down). Yet, the system sleeps after a short while without any warning.
I do not have any 3rd party software installed to manage the UPS, I am using default Windows battery handling. My advanced power settings when on battery are as follows:
- Sleep after: 20 Minutes
- Critical battery action: Sleep
- Low battery level: 20%
- Critical battery level: 10%
- Low battery notification: On
- Low battery action: Do nothing
- Reserve battery level: 7%
When the system sleeps, following entry is shown in the event log:
The system is entering sleep. Sleep Reason: Battery
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<System>
<Provider Name="Microsoft-Windows-Kernel-Power" Guid="{331C3B3A-2005-44C2-AC5E-77220C37D6B4}" />
<EventID>42</EventID>
<Version>2</Version>
<Level>4</Level>
<Task>64</Task>
<Opcode>0</Opcode>
<Keywords>0x8000000000000004</Keywords>
<TimeCreated SystemTime="2012-08-01T06:55:18.358031800Z" />
<EventRecordID>325242</EventRecordID>
<Correlation />
<Execution ProcessID="4" ThreadID="48" />
<Channel>System</Channel>
<Computer>xxxxx</Computer>
<Security />
</System>
<EventData>
<Data Name="TargetState">4</Data>
<Data Name="EffectiveState">4</Data>
<Data Name="Reason">2</Data>
<Data Name="Flags">0</Data>
</EventData>
</Event>
I have found a user reporting and solving a similar problem on Microsoft Answers, in his case the cause were broken drivers for Iomega drive. While I have quite a lot of devices connected to the computer, I do not have any Iomage drive.
- Is there any systematic way how could I troubleshoot this problem or identify which particular device is malfunctioning and causing the computer to sleep?
- Does some documentation for "Microsoft-Windows-Kernel-Power", which would help me understand the exact source of the event?
Best Answer
I was not able to solve the issue despite of my efforts. I was not even able to get any more information on the "Microsoft-Windows-Kernel-Power" so far.
The best I could do was a workaround: instead of using native Windows battery management I have installed APCUPSD software and I can no longer observer the issue. With this sotware Windows are not aware of the battery, the APCUPSD controls shutdown directly and I have verified it is not doing so prematurely.
I guess using APC provided PowerChute might work as well, but I did not like the sofware much when I installed it, sounds too much cluttered and obtrusive to me.