Just because Windows Vista Service Pack 1, RTM'd on February 4, 2008, is out and about, it does not mean that you can get your hands on the final bits. In fact, there is a total of eight reasons that can prevent end users of Vista from accessing the gold bits of the service pack, even after Vista SP1 was made available for download via Windows Update, on March 18, 2008. It must be specified, at this point in time, that the eight issues are valid only in scenarios involving the accessing, downloading and installing of Vista SP1 via Windows Update. The standalone packages of Vista SP1 for English, French, German, Japanese and Spanish, are not affected by any problems, and downloads through the Microsoft Download Center are free for the taking.

"If in running Windows Update you do not see Windows Vista SP1 listed, there are a number of good reasons for this (eight in fact)," informed Nick White, Windows Vista Product Manager. All the reasons exemplified by the Redmond company will prevent SP1 to be delivered via Windows Update or Automatic Updates on Vista RTM machines.

"You have not yet installed all the prerequisite packages you need for Windows Vista SP1. To install them, visit the Windows Update control panel and click on 'check for updates.' You have a pre-release version of SP1 and need to uninstall it before installing SP1. You already have it. To determine if you already have SP1 installed, Open the Start Menu, right click on Computer and left click on Properties," White explained.

At the same time, users have to be aware of the fact that they can only integrate SP1 into Vista SP1 as long as both the service pack and the operating systems they are running share the same language. "We released SP1 in these 5 languages: English, French, Spanish, German, and Japanese. If you have any other language installed, SP1 will not yet be offered to you. (You might not even know if you have an additional language installed! Check the Language control panel to see what languages you have installed) Back in February we announced that we'd be using Windows Update to help make the update as seamless as possible for our users. Windows Update will detect drivers that we know may be problematic when updating to SP1 and will not offer the service pack until an update has been installed," White added.

If you, or the system administrator, have set up the Windows Service Pack Blocker Tool to block the serving of Vista SP1 from AU and WU, the service pack will not be available. At the same time, there could be inconsistencies in the file or registry structure of your copy of Vista RTM preventing the deployment of SP1. Vista SP1 doesn't play well with a number of device drivers. In order to ensure the best user experience possible, Microsoft is not offering SP1 to machines running Vista that feature the faulty drivers.

Vista SP1 will also not be made available via WU and AU if "you used the third-party program vLite to configure the system, and you may have removed required system components that have to be available for Windows Vista SP1 to be installed," according to Microsoft's full list. "[Or if] you see one or more updates for Windows Vista when you run Windows Update. However, you do not see Windows Vista SP1 listed."

Windows Vista SP1 RTM Standalone can be downloaded from HERE.