Vmware Time Sync

October 19, 2006 · 1 min read

If you want to completely disable time synchronization in the guest, 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

If instead you want the guest to have a constant offset from real time as maintained by the host, you can use the rtc.diffFromUTC option, or simply set the CMOS TOD clock time from the virtual machine's BIOS setup screen or from within the guest operating system. In Microsoft Windows, setting the system time automatically updates the CMOS clock.

If you want, you can force the CMOS TOD clock's offset to be initialized to a specific value at power on. To do so, set the option rtc.diffFromUTC in the virtual machine's.vmx configuration file to a value in seconds. For example, setting rtc.diffFromUTC = 0 sets the clock to UTC at power on, while setting rtc.diffFromUTC = -25200 sets it to Pacific Daylight Time, seven hours earlier than UTC. The guest operating system can still change the offset value after power on by writing directly to the CMOS RTC.

For more info see

This article is part of the GWB Archives. Original Author: AJ GB

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