Some of the finer points on Windows Vista SP1 availability

Why are some Windows Vista users who have Windows Update turned on not able to see or obtain SP1, even though Microsoft made that code available on March 18?

The answer to that thorny question and a few more (though not all) of the latest specifics regarding Vista availability are on the Vista Team blog in a new posting by Program Manager Nick White.

"If in running Windows Update you do not see Windows Vista SP1 listed, there are a number of good reasons for this (Eight in fact, see the whole list)," White blogged.

Among those reasons:

• You have not yet installed the prerequisite packages need to be installed on your Vista PC first
• You need to uninstall pre-released versions of SP1 before installing SP1
• You already have SP1 installed (from MSDN, TechNet or some other channel) and don't realize it
• You are running a driver that Microsoft has deemed problematic; SP1 won't be offered to you until the driver vendor has made an update

Which drivers were the "offending" ones that resulted in Microsoft holding back on distributing widely SP1 after it was released to manufacturing in early February? My ZDNet blogging colleague Ed Bott points to the Microsoft Knowledge Base article that lists the drivers that needed updating.

And what about the prerequisite that led to "endless-loop" problems noted by a number of users attempting to grab SP1 via Automatic Updates? Microsoft says they identified the cause of the problem, but haven't completely fixed it yet. On the 18th, White blogged:

"By temporarily suspending automatic distribution, and making a small change on our Windows Update server, we believe we've largely eliminated this problem (and our support call volume reflects this).  We did find one aspect of the problem that was exacerbated when the update was installed using automatic updates.  For this issue, we're planning to release an additional update before we resume automatic distribution of the Servicing Stack Update."

Microsoft isn't going to "push" Vista SP1 to users until April; users who don't yet have SP1 but want it before that need to go into Windows Update and get it.