Microsoft has made available a second release candidate of Windows Vista, and said it expects this to be the final release before the shipping version is unveiled. At the same time, the company is shutting down its Office 2007 preview programme in preparation to ship the productivity suite.

Windows Vista RC2, alternately known as Build 5744, is available now to technical beta testers and MSDN/TechNet subscribers, Microsoft said, and for a limited time to customer preview programme participants. Availability of the final version is still set for November 2006 for volume customers, with general availability coming in January 2007.

In a letter to technical beta testers, Microsoft's Platforms and Services co-president Jim Allchin said the new Vista build has thousands of quality improvements over Windows Vista RC1, which shipped in early September. These include improvements in performance, application compatibility, and fit-and-finish work.

The availability marks the penultimate step in the Vista roadmap before the release to manufacturing (RTM) of the final code sometime in the near future.

"We are just around the corner from RTM and shipping this great product to the world. This will be the last build made available prior to RTM," Allchin wrote.

Microsoft said it is distributing RC2 to a limited number of technical customers to get specific feedback focused on areas of the product that continue to be refined, such as application compatibility and the install process.

The firm warned that this build will not have the same level of updates and support via Windows Update as RC1 has, and testers may not be able to upgrade from this build to the final version of Windows Vista.

Microsoft also announced that Office 2007 will RTM in the next few weeks, and that its Office Preview site will shut down on October 25. Testers will no longer be able to download the Beta 2 Technical Refresh after this date, and technical support will be transferred to Microsoft's main support site ahead of the availability date.