Microsoft plans to debut serving Windows Search 4.0 automatically to Windows Vista Service Pack 1 by the end of July. With the final version up for grabs through the Download Center since the beginning of June 2008, the Redmond company is now wrapping up Windows Search 4.0 for delivery through Windows Update. However, only users with Windows Vista with Automatic Update enabled will receive the update by default; Windows XP users running either Service Pack 2 or Service Pack 3 will have to perform a manual upgrade.

"Windows XP users will see Windows Search 4.0 available as an Optional update, which means you must visit the Windows Update Web site to install it. Windows Vista users with SP1 installed will see the update as a Recommended update. This means that, if a Windows Vista user has set their machine to automatically install updates, Windows Search 4.0 will automatically install on PCs running Windows Vista SP1. The release of Windows Search 4.0 to Windows Update will be gradual for these users," revealed a member of the Microsoft Update team.

This means that some Vista SP1 machines will not get Windows Search 4.0 automatically when it becomes available through WU. In this context, end users have two options available, they can either upgrade manually with the bits offered through the Download Center or wait until Windows Search 4.0 is available for download via Windows Update and deploy it ahead of the AU infrastructure. At the same time, Microsoft offers Vista users with Automatic Updates enabled the possibility to block the automatic delivery of Windows Search 4.0.

"One thing you should note: In order to make search functionality more efficient and reliable, the Windows Search team updated the structure of the search index in this release. This requires re-indexing users' data. The re-indexing occurs in the background after the installation is completed and a reboot has been performed. The cool part? Windows Search will release most of the requested resources and slow down the indexing process as soon as it detects mouse or keyboard activity, or when another application requires computer resources," the MU team representative added.

Windows Search 4.0 is available for download here.
The Multilingual User Interface Pack for Windows Search 4.0 can be downloaded from here.