My laptop’s clock seems to get out of sync and fall behind quite often. I suspect it’s because the clock frequency keeps changing thanks to the power-saving SpeedStep stuff. However, it’s irritating that my clock is always wrong–especially when Windows XP has a built-in NTP client! Of course, the default is to poll once a week (!) … and the “Date and Time Properties” dialog doesn’t allow you to configure how often to poll.
Luckily, it is configurable through manual modification of a Windows registry value. It’s in the registry hive, here:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\W32Time\TimeProviders\NtpClient
The value is SpecialPollInterval which is a DWORD number of seconds that is set to 604800 (one week) by default. I’ve ratcheted it down to 3600 (one hour) to minimize the drift of my clock but not putting undue stress on my local NTP server.
Once you’ve made the change, you’ll need to restart the Windows Time service in order for it to pick up the new interval. From a Command Prompt:
C:...> net stop "Windows Time"
The Windows Time service is stopping.
The Windows Time service was stopped successfully.
C:...> net start "Windows Time"
The Windows Time service is starting.
The Windows Time service was started successfully.
That’s it. You’ll want to click the “Update Now” button in the “Internet Time” tab under “Date and Time Properties” to force a NTP sync. and update the “Next synchronization:” date with your new poll interval.
I hope this tidbit is useful to anyone else looking to adjust the polling frequency of their Windows NTP client. I know this has certainly bothered me for a long time before I finally figured it out.
Update 2018-07-10: Some time between 2007 and 2018, Microsoft published and made publicly available documentation on the Windows Time Service, for anyone who’s looking for it.
Tags: Microsoft Windows, NTP, registry, hack
Programmer, husband, father, singer, guitarist, tinkerer, reverse engineer, strange, and living in New Jersey. 
Just brilliant! the battry backup on the motherboard is dying and this is just works fine! Better than installing extra software. Thanks
Ash: I’m glad it was helpful to you! Thanks for stopping by.
Thank you for this blog entry! It has been extremely bothersome with the clock drifting and Windows NTP not polling often. Micrsoft should really make these parameters tunable via the control panel.
Unfortunately time.windows.com doesn’t seem to be up to date with the daylight savings dates we have in NZ. Any suggestions for how to get around this? Daylight savings time here now starts on the last weekend of September (previously the second weekend of October). Any suggestions on how to fix this? Why does the time server not identify this correctly?
Philip: This isn’t (necessarily) an issue with time.windows.com or any other NTP server. The Network Time Protocol (NTP) distributes time in UTC/GMT. It is up to the operating system running on the NTP clients (i.e., your computer) to know what timezone it is in, and compute the local time accordingly.
What OS are you running? Presumably there should be a patch or update to your OS that should correct the change for DST in your time zone.
Thanks Dossy, you were right. I am running Windows XP and for some reason automatic updates are not running (the bane of my life). Anyway I used a utility called TZEdit to edit the daylight savings start and end dates manually. Then I had to tick the “automatically apply daylight savings” box off, hit apply, then tick it on again and apply. And voila the time adjust correctly. Thanks for pointing me in the right direction.
Philip: Glad you could get it sorted out! Thanks for letting us all know what your solution was – hopefully it can help someone else, as well.
this has saved me tons of time to fix our source code syncing problem
Dossy,
I have several old DVR’s that need the correct time, all the time. It was a lot of work going around to each one and forcing the update. Thanks for awesome little trick that makes my life easier!!
bd
Hi Dossy,
I have windws vista workstation currently pointing to 2 RHEL time server. But when the primary time server is down, this vista w/s doesn’t sync from the secondary time server. Then when i manual sync from the clock , I got error message that ( primary server is down )How should I resolve it ?
How are you configuring Vista’s NTP client to point to more than one time server? As far as I’ve ever been able to find, Windows only lets you configure one NTP server to sync time from.
thanks! works on windows 2003 server ;)
Thanks, it seems my old laptop which is being used as a home server has some trouble keeping proper time recently. It now syncs every 5 minutes to (from) my router.