Microsoft is closing in on the final stage of Windows Vista SP1's availability. In this context, the service pack is being wrapped up for delivery through Windows Server Update Services. Windows Vista SP1 was released to manufacturing on February 4, 2008, and to the general public on March 18. In addition, the automatic distribution of Vista SP1 debuted on April 23. Ahead the gold bits of the service pack being served through Automatic Updates, the company also published Vista SP1 on the Microsoft Update catalog on March 25, from where WSUS users could grab them. Now the software giant is preparing to make Vista SP1 RTM available through WSUS.

But before that, users running WSUS on Windows 2003 servers are advised to deploy the WinVerifyTrust update. Without it, servers in the scenarios described above will continually re-download Vista SP1 binaries once the service pack has been approved.

"We'd like to let you know that, in order to make sure all customers are well protected, we will be marking this particular update as mandatory, which means it will appear in the Updates/WSUS Updates node of the Admin console, and will be auto-approved by default (since the 'Advanced/WSUS Updates' checkbox is checked by default in Options/Automatic Approvals)," revealed Cecilia Cole, WSUS Program Manager.

Windows XP SP3 was published to WSUS on May 3, 2008, but the third and last service pack for XP did not come across the same problems as Windows Vista SP1. With the focus now on the WinVerifyTrust update, Microsoft failed to pin point the release date of Vista SP1 to WSUS.

"After this update has been marked as mandatory to WSUS for a short period of time, we will release Windows Vista Service Pack 1 to WSUS. We believe that this change will help make sure all customers have a good experience once SP1 is released to WSUS, and will also ensure that WSUS can be used to deploy other large updates we may release in the future," Cole revealed.

Windows Vista SP1 is available for download here.