Why can't I have SP1 today?

Microsoft is blaming hardware makers and their drivers, which is, as far as we know, a first.

"We're taking the next month or so to continue our work of identifying as many of these devices as possible," Nash said after explaining the unusual rollout of SP1 that will give the update to some, but not all, users, depending on what drivers are installed on the PC.

Which drivers block SP1?

Microsoft isn't saying.

How do I get it, assuming I can?

Consumers and businesses that don't manage updates from the server will receive SP1 via Windows Update (or Microsoft Update, the alternate that adds in Office updates), just as with any monthly security update or one of the end-of-the-month nonsecurity fixes that Microsoft has taken to releasing.

Systems managed with Windows Server Update Services (WSUS) will receive the SP1 update, assuming the IT staff approves the upgrade. But note that WSUS has trouble with extra-large files and apparently must be updated with a hot fix, according to this recent blog from Microsoft.

Other IT managers, however, will probably use the stand-alone installers -- Microsoft is offering two, one with just five language packs, the other with 36 -- to push the update to their users. Those will be available from Microsoft's Download Center.

How big is Vista SP1?

The short answer: bigger than it was six months ago. Then, Microsoft pegged the package at 50MB that would be delivered via Windows Update and Windows Server Update Services. That has grown to approximately 65MB. (In comparison, Windows XP SP2 weighed in at a hefty 266MB.)

The stand-alone service pack installers designed for businesses are considerably larger: about 550MB for the version that comes with all 36 language packs, approximately 450MB for the edition with just five packs (English, German, Japanese, French and Spanish).

New PC installations, of course, will be accompanied by a slipstreamed DVD with the new bits integrated into Vista RTM, so size, ironically, doesn't matter there.

What if I don't want SP1?

Consumers and businesses using Windows Update who have Automatic Updates set to "Install updates automatically (recommended)" will automatically receive SP1 -- it will both download and install without any user action -- starting in April. (That's assuming the destination PC doesn't have any of the blocking drivers on it.) So that setting must be changed to block SP1.

Either the "Download updates, but let me choose whether to install them" or "Check for updates, but let me choose whether to download and install them" settings will work. The latter, however, will prevent the 65MB or so download from tying up bandwidth. To decline SP1 and remove it from future update lists, right-click it and select "Hide update."

Bigger businesses, however, can deploy the blocking tool Microsoft posted in early December to keep SP1 from reaching their PCs. The blocker, which comes in three flavors -- an executable, a script and a group-policy template -- will prevent SP1 from installing for only 12 months from what the company has termed "general availability." However, when that clock starts is unknown, since the actual rollout date of SP1 is confusing at best and, at worst, incredibly murky.

(The same tool can be used to block both Windows XP SP3 -- which is slated for release sometime in the first half of 2008 -- and Windows Server 2003 SP2. The former will be blocked for 12 months from the date of general availability, but the latter is barred only through next month.)

Windows Service Pack Blocker Tool kit can be downloaded from here.