Completely disable Date and Time sync in a Hyper-V VM

Question

No matter what, a Hyper-V virtual machine keeps finding ways to sync time with the host.

I have:

• Disabled the time synchronization service
• Disabled Windows time synchronization on the guest machine
• mapped time.windows.com to 127.0.0.1 on the hosts file on the guest machine
• used the Security Policy console to remove all users from being able to set date and time

What's interesting here, is that somehow Windows resets the last point (security policy) and adds back LOCAL SERVICE to the list of users allowed to set date and time. This is a totally unexpected behavior to me.

Anything I am missing?

Solution 1

How about unchecking Time synchronization option in Integration Services under VM settings?

Solution 2

Hyper-V guests always synchronize time with the host on BIOS level during boot. Try to specify the time zone properly, otherwise you can manage time in Active Directory.

You can check the following link: https://blogs.msdn.microsoft.com/virtual_pc_guy/2010/11/19/time-synchronization-in-hyper-v/

Hope it helps.

Solution 3

In addition to the answer that suggests to stop "Windows Time" and "Hyper-V Time Synchronization Service", I found that you not only need to stop it, but to deactivate the "Windows time" service. If not it will be restarted.

Solution 4

For anyone still looking for this answer, there are 2 services in the VM that need to be stopped - "Windows Time" and "Hyper-V Time Synchronization Service". When I stop (and disable) both of these services then I'm able to set the clock in my VM and it doesn't get reset, even after a reboot.

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Comments

[resle]

That's the first thing I did

[resle]

Hi Stuka. Thanks, I am aware of the boot time sync. However I was able to disable it. Again, by removing LOCAL SERVICE from the users allowed to set date and time, through the Security Policies console. The only problem is that the user keeps being added again automatically at some point after boot time. (I don't understand the suggestion about time zone as I am skipping time zone entirely, in fact I want to freeze time. Also, I don't have an active directory at all)

[Stuka]

I am not sure that there is any way to completely freeze time in Hyper-V, but if it exists, I wanna warn you that it can highly affect your VM because almost all the services and applications are dealing with the Windows date&time service. You can find steps for completely disabling time synchronization by following the link below: experts-exchange.com/questions/26453055/…

[I say Reinstate Monica]

This doesn't prevent the VM from being synched to the Host's clock at VM startup.

[resle]

Not for me. Even with this being disabled, the machine still somehow syncs at times. Note that the VM in question is running Windows 10