The first public build of Windows Vista Service Pack 1 is imminent and is planned by the end of this week. Microsoft has already made available Vista SP1 Release Candidate 1 via Connect, MSDN and TechNet, and is preparing for the next step, opening up the beta testing process to the general public through the Microsoft Download Center. This being the case, users interested in running a pre-final release of the first service pack for Vista, should gear up for the upcoming release. The methods presented below apply to Vista SP1 RC1, as well as earlier releases of the service pack.

The installation of Vista SP1 RC1 is a simple enough process, and users will have a wizard guiding them through the deployment. However, users that have been involved in earlier testing stages of Vista SP1 need to uninstall previous builds of the service pack. The catch here is to wait a healthy period of time, even as much as 30 minutes after uninstalling a previous version of Vista SP1, before attempting to integrate build RC1. Alternatively, following the removal of older variants of the refresh, users can also check the status of the previous installation by running: "reg query HKLMComponentsDerivedDataComponents | findstr /i /c:"-ntdll_" | findstr 6001.170" at a command prompt. If versions prior to 6001.17047 are listed in the output, you'll just have to give it more time.

Now, to the actual uninstalling of Vista SP1. The process is rather simple and it involves the Package Manager. All that users have to do is open a command prompt with elevated privileges. In order to do so, simply type "cmd" in the Search box under the Start menu and right-click selecting "Run as administrator" from the contextual menu that will pop up. Identify the build number of your previous Vista SP1 installation and put in the following command: "start /w pkgmgr /up: VistaSP1-KB936330~31bf3856ad364e35~x86~~6.0.0.". This is obviously valid for 32-bit machines. On 64-bit computers replace "x86" with "amd64". For confirmation enter "winver" and press Enter in the Run dialog box.