If your organization uses Microsoft's blocker tool to prevent installation of the latest service packs for Windows Vista and Windows XP, Microsoft is giving notice: The hand that giveth also taketh away. Microsoft Service Pack Blocker Tool for Windows Vista SP1 will expire April 28, 2009 and the blocker tool for Windows XP SP3 will expire May 19, 2009.

After those dates, if Automatic Update is turned on, Windows Update will alert users about the service pack updates, and it will be up to them to decline or ignore the update if they don't want it. If Automatic Update isn't turned on, Windows Update will deliver the service packs but only if users open Windows Update to check for available updates and accept the installation. The Windows Team blog entry for January 29 offers more info and FAQs in "Expiration of Service Pack Blocker Tool for Windows Vista & Windows XP."

To get more info on Windows Update and Automatic Updates:

Automatic Updates and Exchange Server 

Microsoft Issues a Head's Up on Windows Update Changes

To see other IT pros' experiences, tips, and tricks concerning Vista:

Vista Migration: Things I Wish I'd Known

10 Reasons to Deploy Vista

10 Reasons Not to Deploy Vista