Nick —”A HotFix.net blogger today posted a collection of individual Windows Vista hotfixes as a supposed Windows Vista Service Pack 1 (SP1) preview. However, those of you who've been closely following discussions on Windows Vista will quickly notice that what is posted consists of some material already available on Windows Update and some hotfixes that we give out on a case-by-case basis, along with a lot of speculation about what may and may not be included in SP1.”
Looking at the site, it seems to me the blogger compiled a list of previous mentions of SP1 (purely conjectural, and already discussed in other blogs) stitched together with another list of "hotfixes" mentioned in various KB (Knowledge Base) articles (again, already posted on our web site). You probably already know that we create and release hotfixes on a regular basis for very specific customer scenarios or for OEM-shipped machines, and that it's standard policy that all hotfixes are rolled into the next service pack release. However, a service pack is not just a compilation of hotfixes and security updates, so don't make the mistake of thinking that the set of fixes offered in this particular blogger's list represents a preview of the service pack itself.
It's worth mentioning that hotfixes not posted on Windows Update are not intended for individual installation unless the user is experiencing the specific symptoms mentioned in the corresponding KB article. These hotfixes represent specific fixes for specific customer scenarios and typically have not undergone full regression testing. When they are integrated into a future service pack, they will receive full regression testing and beta testing. So, installing a collection of unnecessary hotfixes may cause more problems than are fixed.
The bottom line is that unless you have encountered the specific situation described in a given KB, you'll get everything you need from Windows Update.
Source:→ Vista BlogMicrosoft, Windows Vista, Service Pack, SP, Update, Hotfixes