This morning, Microsoft finally made Windows Vista Service Pack 1 (SP1) available broadly to the public, fulfilling a promise it had made early last month when it announced the release to manufacturing of this major Vista update. (See my article, Windows Vista Service Pack 1: Here It Comes Ready or Not, for more information.) More important, perhaps, the company has answered a lot of questions that I and many others had raised in the wake of SP1's release to manufacturing, centered on the delay between RTM and general availability (GA). Here's what happening.

Service Pack 1 is finished ... No SP1 for you!

Microsoft announced that it had released Windows Vista Service Pack 1 (SP1) to manufacturing on February 4, 2008. (The company also released Windows Server 2008 to manufacturing on the same date, as Vista SP1 and Windows 2008 are based on the same code base.) However, in a move that angered enthusiasts, Microsoft also announced that SP1 would not be made available immediately to the public. Instead, the company outlined a semi-vague schedule during which SP1 would be slowly rolled out. This schedule was updated a few days later, and looked like the following:

  1. Beta testers received the final SP1 code immediately.

  2. Volume licensing customers received the SP1 code on DVD within a week of RTM.

  3. SP1 was made available to MSDN and TechNet Plus subscribers later in February.

  4. Broad availability of the English, French, Spanish, German and Japanese versions of SP1 would happen between mid-March and mid-April, depending on your hardware configuration. (Other languages would RTM in mid-April and begin appearing after that.)

That last bit was the most confusing: If SP1 was done, why would Microsoft need to wait at least a month and a half before broadly deploying it to customers? The company said at the time that an unspecified number of hardware drivers were "known to be problematic," which would delay the SP1 release. But Microsoft never explained what these problems were, how serious they were, or which hardware devices were affected. And in the meantime, hundreds of thousands of Vista users have upgraded to SP1 via MSDN, TechNet, and other means, and there have been no reports of any problems at all.

Here comes SP1

On Tuesday, March 18, 2008, a day that might accurately be described as occurring in mid-March, Microsoft announced the immediate public availability of Windows Vista Service Pack 1 (SP1) via both Windows Update (WU) and the Microsoft Download Center. As previously promised, this initial release is for the first wave of five languages (English, French, German, Japanese, and Spanish), and all remaining language versions are still expected in mid-April.

I discussed this release with Microsoft's John Gray and David Zipkin, both of whom seemed eager to explain the events of the past six weeks or so. Amazingly, the company has also thoroughly documented which drivers were causing issues with SP1, and Gray and Zipkin expanded on that to help explain the issue further.

Put simply, Microsoft identified 12 specific driver issues that would, in very rare circumstances, cause issues for customers upgrading from Windows Vista to Service Pack 1. As it turns out, most of these issues were actually fixed between the last SP1 release candidate (RC) and the final build, but because they were issues with hardware drivers and not something that Microsoft could patch in SP1, the company felt it was best to hold off on SP1's GA until the problems were fixed. So Microsoft has been working with its hardware partners to get updated drivers created that it could then distribute to customers via Windows Update.

These issues, such as they are, aren't particularly serious. What happens is that Windows reinstalls device drivers when upgrading to a service pack. In some cases, with the affected devices, this reinstallation could cause some problems, which might range from a loss of configured settings to a reversion to default settings. In very rare instances, some functionality might be temporarily lost. For example, with some audio drivers on certain systems, an upgrade to SP1 might disable sound output. But in such cases, a quick visit to the Control Panel would typically fix the problem. Worst case scenario: You might have to reinstall a driver manually.

The reason this was taken so seriously was that Microsoft realized that while beta testers might be technical enough to deal with such an issue, this kind of thing could be confusing to regular customers. So it wanted a plan in place to ensure that most users would never experience any problems.

What Microsoft has done is configure Windows Update to evaluate each Vista system and determine whether they have any of the affected hardware devices. If they do, Windows Update will not show SP1 as an available update but will instead show the updated drivers. Once these drivers are installed, SP1 will be made available automatically. Beginning today, these updated drivers and SP1 are being made available via WU. But the updated drivers are currently listed as optional updates. In the coming weeks, they will be recategorized as important updates, causing WU to automatically download and install them on many systems. Thus, over time, most users will simply get whatever prerequisites they need, followed by SP1.

Of course, for readers of this site as well as other technical users, such niceties are not necessary. So Microsoft is also making SP1 available for manual download from the Microsoft Download Center. The feeling here is that if you're technical enough to go look for this download, you can probably handle any little issues that may come up. Makes sense.

What went wrong?

You may be curious about which device drivers were causing issues with SP1. (I certainly was.) The list includes certain versions of five audio drivers (RealTek AC'97, two versions of SigmaTel, Creative Audigy, and Conexant HD Audio), two biometric fingerprint sensors (AuthenTec and UPEK), Intel Display, a Texas Instruments Smart Card Controller, the Sierra Wireless AirCard 580 with the Watcher.exe application, and the Symantec software driver for the Symantec Endpoint Protection and Symantec Network Access Control clients. The complete list is available on the Microsoft Knowledge Base.

Most of these issues are fixed, and any remaining issues will be fixed by mid-April. But it's worth reiterating that the majority of people who use these devices and upgrade to SP1 will experience no issues at all. In rare cases, a configuration change or maybe a driver reinstall might be required. But that's the extent of it. "Most of the problems are with audio drivers," Zipkin told me. "But people who have those devices will likely have a smooth install. You may have to reinstall a driver. But we also have service pack support techs who can handle these issues as well." That's an important point: Because Microsoft offers service packs to customers, they support them directly, regardless of how you obtained Windows Vista. So you've got free email-, online chat-, or phone-based support waiting for you if something does go wrong.

It's also worth noting that there are other, non-driver-related reasons why you might not see SP1 on WU. For example, if you're using a language version that isn't supported in the initial wave of five language versions, you won't see SP1 until mid-April at the earliest (this will be true of Vista Ultimate and Enterprise users who have installed various language packs as well). And if you installed a pre-release version of SP1, you'll have to uninstall that first; otherwise, SP1 won't appear in WU. There are a few other less likely causes as well. Check the Microsoft Knowledge Base for details.

Go get SP1

So, here's the schedule. If you absolutely, positively have to have SP1 right away, it's available from the Microsoft Download Center and probably from Windows Update as well, depending on your hardware configuration. I recommend hitting Windows Update first regardless, because at the very least you may see some updated drivers. Install those first. If you can install via Windows Update after that, do so: This install will be quicker and involve a much smaller download than the full download that's on Download Center.

If you're not that technical or in no rush to install SP1, feel free to wait. Over the next month or so, Microsoft will probably make a number of drivers for your system available via Windows Update. These drivers will be optional at first, but will turn into automatic installs after a few weeks. By mid-April, your system should have automatically downloaded and installed all the updates you need. At that point, if not before, you will see SP1 available. Note that SP1 will never be installed automatically. Instead, Windows Update will download the update and then prompt you to accept the installation. It will not be installed until you explicitly agree that it should do so.

However you choose to do it, my advice is simple: All Windows Vista users should upgrade to SP1 as quickly as possible. SP1 is a major update to Windows Vista that improves the product's performance, compatibility, and reliability, as noted in my review. There's just no reason to wait, especially now that we know how insignificant the previously-reported hardware issues are.