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Windows 11 has recently started assigning the wrong time zone to two computers when the option to "set time zone automatically" is enabled. When I disable this option, I can set the correct time zone, but immediately after I re-enable it, the time zone reverts to the incorrect one.

I would like to know if there are any logs that would enable me to diagnose this failure.

I assume that the logic is roughly as follows:

  1. Physical location is determined from IP address or other indicators.

  2. IANA time zone is determined from physical location.

  3. Windows time zone is determined from IANA time zone as described at How to translate between Windows and IANA time zones (in particular as specified here).

I've confirmed that the computer's location service is reporting the location correctly, and I've confirmed that the mapping in Windows zones.xml is correct. I therefore suspect that the second step above is being performed incorrectly, and I would like to see whether that's the case. If there is a log somewhere that traces the logical steps from location to time zone in any detail, that would help.

I noticed that there has been a recent change to this aspect of Windows. This behavior seems to have started a few weeks after the update was installed, so I wouldn't think it's related, but on the other hand it's very recent, and I might have misunderstood something about the timing of the update. In particular, if the update changed the resolution with which Windows identifies the IANA time zone, it could cause this behavior, as the incorrect time zone is between 5 and 15 km away in almost every direction. The date of C:\Windows\Globalization\Time Zone\tzautoupdate.dat is 2023-12-12. I assume that this is the shape file used to translate between locations and time zones, though it doesn't have any IANA names, so it's possible that the IANA-to-Windows step is pre-baked into that file.

Is there any way to get Windows to report the IANA time zone? Is it possible to read or otherwise analyze tzautoupdate.dat?

phoog
  • 133

3 Answers3

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do you have dual boot on these machines by any chance?

if you do windows works really bad with that, you need to set the new registry DWORD32 key named RealTimeIsUniversal in

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Control\TimeZoneInformation

and set it to 1

this guide was quite helpful to me

i might be wrong because it's usually the problem with assigning UTC time, not the timezone itself

sergey
  • 39
2

Querying the IANA time zone can be done in PowerShell. The post How can I get the local system time zone as an IANA time zone ID on Windows 10? has this command:

[Windows.Globalization.Calendar,Windows.Globalization,ContentType=WindowsRuntime]::New().GetTimeZone()

If Windows is consistently getting your time-zone wrong, you could disable time-zone auto-update by using sc.exe config like the following (note the blank after start=) :

sc config tzautoupdate start= disabled

To set a fixed time-zone, use the tzutil command like this:

tzutil /s "Eastern Standard Time"
harrymc
  • 498,455
-1

As answered from another question by Clippership.

Quote of the answer in case of link dead:

Check in with your friends - the Windows Event Logs. You may find an application is adjusting the time zone. Filter the System event log for Event ID = 1 or Source = 'Kernel-General'. In our case we found the app named: "MaxproVideoGuardAgent.exe" was changing the Time zone.

Basically after doing the changes in Outlook calendar, timezones, bios, https://myaccount.microsoft.com/ and everywhere in between only the identification of the event that kept reverting my timezone fixed the issue.

user3053452
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