Nick on Windows Vista team blog has announced the releasing of Windows Vista SP1 release candidate via Microsoft Connect, and tomorrow subscribers to TechNet and MDSN will have access to those RC bits too.  In addition, the RC will be available to the public next week via Microsoft's Download Center. The release candidate phase of beta software is typically the final phase before the RTM (release-to-manufacturing) of a product and indicates that the code has attained a significant level of performance and stability.

Let me call out several changes made since the Beta release of Service Pack 1 -- many of which came about as a result of direct feedback from our Beta-testing community (thank you!):

• The size of the standalone installers have decreased significantly. For example, the standalone installer packages consisting of all 36 languages (x86 and x64 chip architectures) are smaller by over 50%. The standalone installer packages consisting of just the 5 languages (again, x86 and x64) slated for initial release are more than 30% smaller in size.
• The required amount of disc space for SP1 installation has also decreased significantly. Furthermore, with the RC, if more space is required to install SP1, an error message will now display exactly how much space is needed to complete the installation.
• Previous SP1 versions left behind a directory of files that wasn't needed after installation and occupied about 1GB of space; the RC includes automatic disk clean-up to remove this directory.
• Installation reliability has been improved based on bug reports and error codes reported from Windows Update (thanks, Beta testers!). Testing shows that these improvements have significantly increased the proportion of successful installations of the RC.
• We've improved the user experience of installing SP1 via Windows Update. During the Beta release, users installed without much guidance from Windows Update. The RC now contains a series of screens with detailed information on SP1.

We also have information to share with IT professionals and system administrators regarding final plans for SP1:  we're on track to complete and release SP1 in the first quarter of 2008.  When SP1 is complete and we reach our release to manufacturing (RTM) milestone, then shortly after the standalone installer will be released to the Web in two waves.  The first wave will consist of the standalone installer (x86 and x64) for the 5 initial languages -- English, French, Spanish, German and Japanese.  These languages will be deployed shortly after the RTM milestone.  The second wave will launch 8-12 weeks after the first and will consist of all remaining languages, for both chip architectures (x86 and x64).

For administrators managing Windows Vista PCs configured to use Windows Update but not wishing to deploy SP1 upon its release, we have a "blocker patch" that will prevent installation of SP1.  Information on the blocker patch can be found here starting tomorrow: http://technet.microsoft.com/windowsvista/bb927794.

If you're not familiar with SP1, you can find more information in this whitepaper.  We built Windows Vista SP1 to address specific reliability and performance issues and also to support new types of hardware and several emerging standards.  Further, SP1 is designed to make it easier for IT administrators to deploy and manage Windows Vista.  Of course, those of you familiar with SP1 already know that some of SP1's improvements are already available via Windows Update.

A reminder to anyone installing the SP1 RC bits: you will need to uninstall the release candidate of SP1 before you can install a later version.

Also, Windows Server 2008 RC1 was made available today for testing; find the download here: http://www.microsoft.com/ws08eval.  And, we announced two updates to the WGA program yesterday:  the first addresses two exploits to the activation process while the second adjusts how Windows differentiates between the genuine and non-genuine Windows Vista experience.  More information can be found here: http://www.microsoft.com/presspass/features/2007/dec07/12-03wga.mspx.

And last, thanks once more to our Beta testing team for their diligence and devotion, as you've made a big impact on this RC release!

Windows Vista, Service Pack, Vista SP1, Release Candidate, RC, Microsoft