Although Windows Vista SP1 is flagged as important it isn't auto installed due to possible driver problems
Microsoft has been offering Service Pack 1 for Vista for installation via the inbuilt Update function since yesterday (Wednesday 19th of March), earlier than originally announced. Although it is identified as an "important update", it is not yet an automatic download and install. Microsoft explains this unusual behaviour in a blog entry: users can now download the lean version of the installation package, which only transfers the files necessary for the installed system, via Windows Update.
But the download must be started explicitly - even if Windows Update is configured to download and install security patches automatically. If SP1 does not appear in the Update window, this could mean that Windows Update has discovered a driver that does not work with SP1. Microsoft's advice in this case is to install an updated driver first, as an optional update.
Microsoft's product manager Nick White says that the postponement of the release of SP1 was used to analyse driver problems and improve the release candidate at many points. Nevertheless, he said, there were still a few machines that gave trouble. Microsoft has published a list. He said some updated drivers were ready now as optional updates, and in a few weeks they too would be delivered automatically.
In about a month, he predicted, the next "update wave" (Wave 1) of SP1, which covers 31 further language versions, would reach Vista PCs (at the moment only German, English, French, Spanish and Japanese Vista PCs install the update). Windows Update would then download SP1 automatically and even users who did not actively seek SP1 would be welcomed by an installation dialogue on the desktop, which they could reject if they wished.
Microsoft is providing a downloadable blocker patch for administrators who do not want Vista to download SP1 automatically in April.