Microsoft has given the green light to Windows Vista Service Pack 1 RTM downloads... again. Released to manufacturing on February 4, 2008, the availability saga of the first service pack for Vista is now in its final stage, namely delivery through Automatic Updates. Two days after the RTM of Windows XP Service Pack 3, Microsoft started pushing Windows Vista SP1 through AU. In this manner, the service pack was delivered and deployed automatically to all Vista RTM users that had Automatic Update enablers.

On April 29, the day Microsoft was supposed to start serving the gold bits of XP SP3 Build 5512 via Windows Update and the Download Center, the company revealed that it was postponing the availability of the last service pack for XP, as well as discontinuing the distribution of Vista SP1 through AU due to an incompatibility problem. According to the Redmond company, both service packs had issues integrating with the Dynamics Retail Management System.

Since last week, Microsoft has built and set up a filter on Windows Update designed to prevent the two service packs being offered to Microsoft Dynamics RMS customers. The company advised Dynamics RMS users not to install any of the service packs and for those that have already deployed Vista SP1 and XP SP3 to contact Microsoft Customer Support Services. Still, with the filters now in place, Vista SP1 RTM downloads through AU are live yet again, even though the service pack was available all along on WU and the Download Center.

"You may have heard about an incompatibility Dynamics Retail Management System has with SP3 and Windows Vista SP1- we've added a filter to block WU from offering Windows XP SP3 or Windows Vista SP1 to systems w/ RMS for now and will make a fix available soon. You may have also heard that we temporarily suspended automatic distribution of Windows Vista SP1 for this - we're now also happy to report that we've resumed automatic distribution of Windows Vista SP1," revealed a member of the Microsoft Update Product Team.

Windows Vista Service Pack 1 All Language Standalone is available for download here.