Daylight saving time.. (DST).. some love it (due to some extra hours of sleep) some hate it.. because the have to program around it.. and so do the developers at Microsoft.. and then.. there are some countries that like to switch the dates they change the time (Argentina for example).. well all fuzzy logic if you ask me.. and so did the developers think.. and they accidently missed one date.. a date very close to come..(October 25th)

Microsoft has released a DST patch for well almost all products they made, it must be installed, else the time in your forest could go crazy.. and things could break.. so if you would like to know if your environment is at risk, check this list, check your WSUS server and check all your servers/computers that do not use the WSUS (or other patching) server

http://support.microsoft.com/gp/dst_prodlist

and they keep changing the DST’s.. goverments of the world.. make up your mind!

The most recent cumulative update to daylight saving time (DST) and world time zones (TZ) is now available for supported versions of the Windows Operating System via Microsoft Download Center and Windows Update.

Microsoft product teams follow a semi-annual DST and TZ update schedule, which follows the Windows regular schedule for publishing newly legislated DST rules and time zone updates. These annual Windows “Cumulative Daylight Saving Time and Time Zone Updates” are released in December for each calendar year; a semi-annual update will be released in August, as needed. Microsoft products that are affected may also schedule updates to accommodate some of these changes.

December 2009 cumulative time zone update for Microsoft Windows operating systems

http://support.microsoft.com/kb/976098

This update supersedes and replaces update 970653, which was released in August 2009. This update also includes additional time zone changes that were signed in to law after update 970653 was created.

If you have already deployed update 970653, read the descriptions of the specific time zone changes that are addressed in this article to determine whether you must deploy this update immediately. If systems are not directly affected, you can schedule deployment at the next available opportunity.

We recommend that you deploy the most current Windows cumulative time zone update to guarantee the consistency of the time zone database on all systems

Important

• Before you apply the update that is described in this article, be aware of potential issues that may affect Microsoft Outlook.
  For more information about these issues, click the following article number to view the article in the Microsoft Knowledge Base:

931667  (http://support.microsoft.com/kb/931667/ ) How to address the daylight saving time changes in 2007 by using the Time Zone Data Update Tool for Microsoft Office Outlook

• If you are running Microsoft Exchange Server in an Information Technology (IT) environment, you must take additional measures to guarantee the correct operation of Exchange Server. For more information about the Exchange daylight saving time (DST) update, click the following article number to view the article in the Microsoft Knowledge Base: 941018  (http://support.microsoft.com/kb/941018/ ) How to address daylight saving time by using the Exchange Calendar Update Tool

Happy wintertimes!