Now that Windows Vista Service Pack 1 (SP1) is broadly available to the public via Windows Update, I wanted to see what the install experience would be like. Not surprisingly, it's very similar to the Windows Update install experience during the Vista SP1 beta, with one small but significant change: Because of several known problematic hardware device drivers, you may have to install some new drivers before you'll see SP1 on Windows Update.
I tested the Service Pack 1 Windows Update install experience on several different Vista-based PCs I have here. To my surprise, SP1 wasn't ever made available on a few of them. I believe this is because these particular machines have problematic devices for which new drivers have yet to be issued. (Microsoft told me last week that 2/3 to 3/4 of the problematic device drivers have been updated.)
In any event, here's what the SP1 install looks like via Windows Update.
Before you can install SP1, you need to download any required prerequisites via Windows Update first. Most of these should have been automatically installed. However, as documented in It's Here! Windows Vista Service Pack 1 Arrives, Microsoft has identified 12 specific driver issues that can possibly cause problems during an upgrade to SP1. If you have one of the offending devices, you'll need to download updated drivers before you can get SP1. And sure enough, as you can see below, one of my laptops utilizes a Conexant HD Smartaudio device that is on the list. An updated driver is available, so that had to be installed first.
After you install any new drivers and reboot, you should be offered SP1 via Windows Update as an important update. (If you don't see it, that particular PC probably has an affected hardware device that does not yet have a new driver. These issues will all be resolved by mid-April, as Microsoft first announced in early February.) Note that WU will not automatically download and install SP1. However, if you leave your system to its own devices long enough, it will download SP1 and then ask you if you'd like to install it.
Note, too, that the SP1 download Windows Update is significantly smaller than the standalone SP1 installer you can download manually from the Microsoft Download Center. While the size of the SP1 download will vary from system to system (from a minimum of 65 MB to a maximum of 427 MB), the standalone download is a full 434.5 MB. In my case, the Windows Update download was just 66.9 MB.
In the shots below, you can see the installation process in action. The system reboots a few times during which the updated files are applied to your PC. When it's done, you logon as usual and get back to work. The experience should be seamless for most people. It took less than an hour on the test machine.
Given Microsoft's conservative rollout plan for Windows Vista, it shouldn't be surprising that the install experience via Windows Update is relatively quick and painless. The only gotchas will affect those who wish to get the update immediately but can't because they have one of the few problematic devices for which a new driver hasn't yet been made available. In that case, you can simply wait--updated drivers will appear when ready via Windows Update--or proceed to the Microsoft Download Center and download the larger standalone installer.