Configuring Time sync on Hyper-V domain controllers

3 Mar

I’m not really into timesyncing but I ran into an issue on my network that my time was off 10 minutes on my DC’s and servers. With the w32tm /query /source command I could see that my machines all were using the DC with the PDC emulator role enabled. The DC was using the VM IC Time Synchronization Provider as time source.

In my case I wanted my machines to sync from my DC and the DC from the timeservers. Here’s howto:
First use the following command to partially disable time synchronization on your hyper-v dc’s (just overwrite the existing value). Restart your Windows time service when done.

reg add HKLM\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\VMICTimeProvider /v Enabled /t reg_dword /d 0

Now if you use the w32tm /query /source command you’ll see that it uses it CMOS clock for time sync. Which is not good cause you will not have any time synchronization. We need to configure our time source:

w32tm /config /syncfromflags:manual /,,,
w32tm /config /update
w32tm /resync /force

If you now run the /query /source command you’ll see that it uses the specified timesources and time sync will work.


  • Joel, is saying:

    Thank you very much! Your article was perfect . I came across it doing a google search for “change VM IC Time Synchronization Provider” I was a bit unsure about making the registry change without clarifying your information from other online sources.

    It would be good to see screenshots of the actual registry tree and values being changed rather than a reg command run in the command line.

    Afterwards I also ran the command w32tm /resync /nowait to force the sync asap and then w32tm /query /source to confirm the change.

    Thanks again!

    Reply this message

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