Case of the Boot Camp Time Sync Issue

So my Windows 8 installation, in boot camp on MacBook Air, started to have this issue whenever I woke from sleep the time would jump forward 10 minutes, eventually throughout the day the computer may go back to the correct time. However if the time was already wrong it wouldn’t change on wake from sleep.

My time was set to sync with an internet source, selecting ‘Update Now’ would always revert Windows to the correct time:


Normally on Windows Running via Bootcamp the time is kept in sync with the Apple Time Service which I had disabled


I had disabled it because it was unnecessary to keep time in sync via service, but rather Windows could be configured to use “Universal Time” In the past this had always worked…

This had been accomplished by setting RealTimeIsUniversal to 1 under HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\TimeZoneInformation


Re-enabling the Apple Time Service didn’t fix the issue.

Looking to Windows Event viewer I filtered by events in System log from Kernel-General and of Event ID 1.


Here we could see the reason for the time change:

The system time has changed to ‎2013‎-‎06‎-‎11T08:36:59.500000000Z from ‎2013‎-‎06‎-‎11T08:26:56.716112600Z.

Change Reason: System time synchronized with the hardware clock.


So I suspected changing the time in Windows was not updating the Macs hardware clock. This was proved by booting into MacOS – and the time was wrong. I configured the time in MacOS to Set date and time automatically, and the time was immediately corrected. Restarting Windows had the right time now…no more unexpected time changes



About chentiangemalc

specializes in end-user computing technologies. disclaimer 1) use at your own risk. test any solution in your environment. if you do not understand the impact/consequences of what you're doing please stop, and ask advice from somebody who does. 2) views are my own at the time of posting and do not necessarily represent my current view or the view of my employer and family members/relatives. 3) over the years Microsoft/Citrix/VMWare have given me a few free shirts, pens, paper notebooks/etc. despite these gifts i will try to remain unbiased.
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