For a long time now my PC (ordinary physical desktop, no virtualization or anything) has random time changes. It's not ordinary drift, as the offset compared to the actual time is always different, and the jump happens suddenly. Something is actively changing the time to a wrong value. The wrong time is usually within a couple hours of the actual time. I've had enough, and am trying to solve this issue.

So I disabled the Windows time service:

net stop w32time
w32tm /unregister

Then I cleared the Windows event log, manually set the system time to the correct time, and waited. Lo and behold, the system time changed again after a while to a bad time. I checked the system log, and there was nothing in the security log (no 4616 events as there would be if the Windows time service does an update). All that I can find is a System information event that simply says the time has changed, but not what caused it:

The system time has changed to ‎2018‎-‎01‎-‎19T14:45:28.500000000Z from ‎2018‎-‎01‎-‎19T15:41:23.030896800Z.

And in detailed XML form:

<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
<Provider Name="Microsoft-Windows-Kernel-General" Guid="{A68CA8B7-004F-D7B6-A698-07E2DE0F1F5D}" /> 
<TimeCreated SystemTime="2018-01-19T14:45:28.500000000Z" /> 
<Correlation /> 
<Execution ProcessID="4" ThreadID="76" /> 
<Security UserID="S-1-5-18" /> 
<Data Name="NewTime">2018-01-19T14:45:28.500000000Z</Data> 
<Data Name="OldTime">2018-01-19T15:41:23.030896800Z</Data> 

I have no idea how to troubleshoot this further, and find out what is changing the system time. How can I solve this?

  • Guessing timezone or locale related somehow? Does windows think you're in a different timezone, or the daylight savings should be on/off when it isn't/is? – Xen2050 Jan 20 '18 at 13:46
  • @Xen2050 I don't think so, my timezone is set to GMT+1 and doesn't seem to change. Daylight savings also can't explain these effects, as that would only result in +1/-1 offsets, which is not the case. – orlp Jan 20 '18 at 15:41
  • Is the time in BIOS always correct? – user3169 Jan 21 '18 at 7:16
  • @user3169 I just checked, yes, BIOS time is correct. – orlp Jan 21 '18 at 12:36

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