Daylight Saving Time patch and the running admin

What a great day! My phone was ringing constantly for the entire morning of this Monday. All these people were calling IT Dept. because they couldn't change their Daylight Saving Time settings on their computers. One of the users tried to change his time and Outlook 2003's dates went back to 16th century for most of his e-mails.

Our network admin had already patched all Windows XP machines with Microsoft's KB931836 using SMS push on Friday of last week. It didn't work on most computers after the time had actually changed in the US. I started troubleshooting by checking if the patch was properly installed. Yes, it was there but whenever I tried to adjust the time and rebooted the computer, it would show some strange time or it would go back to the wrong time. Some of the Windows XP SP1 computers worked fine with the patch but almost all of the SP2 computers wouldn't accept the new daylight saving time setting.

Finally, I got a registry patch that helped me fix this issue. The following are the steps I used to resolve this issue.

1. Save the TZupdate.reg file on a network shared folder. Download the TZupdate.txt file from here and rename it to TZupdate.reg. (Note: This is only for English builds of Windows and for the US. If you are working on non English builds of Windows, follow the links provided at the end of this post. If you are updating the DST on a single Windows XP SP1/ SP2 machine, save it on the C drive.)
2. Create a system restore point or backup the registry first if you are updating a single machine.
3. Run TZupdate.reg to update the registry's time zone information.
4. Go to Control Panel and open Date and Time. Click on Time Zone tab.
5. Select anything other than your current time zone. Click Apply. Then choose your current time zone. Click Apply. The time should be automatically adjusted to your current time now. Reboot the computer.

Important note: This is somewhat a quick fix for those machines with SP2 that would not change after patching. However, I found that this registry update alone worked on my home computer (Windows XP Pro SP2) without installing the update KB931836. For a production environment, one should consult Microsoft knowledge base articles below and test on a few PCs first.

References:
1. How to configure daylight saving time for the United States in 2007
2. February 2007 cumulative time zone update for Microsoft Windows operating systems
3. Daylight Saving Time Help and Support Center