That point puzzled me for at least 20minutes so I think I need to write something about it in order fix that in my memory.
I used to perform Product validation on Virtual Machines but when last Friday I had to do some test of how a license system is robust against system date & time change, I met a strange behavior!
I tried to change the date on the VM as on my own workstation (after disabling the Windows Time Service (a.k.a W32Time)) but every time I tried the clock got back in sync after few seconds and I didn’t know why. I was searching for a setting in my Virtual Box Host configuration but finally after some tests, I found that my VM was running a specific windows service called “VirtualBox Guest Addition Service”.
His description is really clear:
“Manages VM runtime information, time synchronization, remote sysprep execution and miscellaneous utilities for guest operating systems.”
So if like me you always setup the Guest addition for all VM you create, remember that service and that it use your host date & time to re-sync the guest date & time.
