Time Synchronization In Virtual Machines

Thursday, 02 February 2006 by Michel Roth

Ever run a time-limited demo or beta inside a virtual machine? I bet you have. Then you've probably noticed the negative effects of virtual machines synchronizing their clocks/dates with the host machines. Sometimes you want to set back the date a few months to "extend" time-limited demo or beta.

By default host-guest time/date synchronization is enabled in MS Virtual Server. In VMware date/time synchronization takes place in "suspend mode" and when powering off a virtual machine. Here's how to disable it:

VMware
Open the virtual machine's configuration file (.vmx) in a text editor and set the following options to FALSE:
tools.syncTime
time.synchronize.continue
time.synchronize.restore
time.synchronize.resume.disk
time.synchronize.shrink

Virtual Server
In the Virtual Machines pane, click Configure, and then select the virtual machine that you want to change.
In the Configuration pane, click Virtual Machine Additions.
Click to clear the Host time synchronization check box, and then click OK.