Now that Windows Vista SP1 is out, end users have the possibility to not only install the service pack, but also to make the bits a permanent component of the operating system. Microsoft made available Vista SP1 on March 18 via Windows Update and the Microsoft Download Center, one month and a half after the service pack had been released to manufacturing on February 4. Users of both 32-bit and 64-bit Vista RTM can install SP1 as an update or deploy
it via the standalone packages offered for download. But at the same time, Microsoft delivers the possibility of nailing SP1 down on Windows Vista RTM. This can be done with the help of Vsp1cln.exe.
"You can use the Vsp1cln.exe tool to uninstall the files that are archived after you apply Windows Vista SP1. When you install Windows Vista SP1, the disk space that is used by the operating system increases. This extra disk space is used to archive files so that Windows Vista SP1 can be uninstalled if this is ever necessary. Typically, you should run the Vsp1cln.exe tool if you want to reclaim this disk space after you apply Windows Vista SP1, but only after you have decided that you do not intend to uninstall this service pack," Microsoft explained
Vsp1cln.exe is essentially designed to make your installation of Vista SP1 permanent. Otherwise, end users are able to uninstall the service pack. In Control Panel, through the View Installed Updates option in the left hand side panel, Vista SP1 can be uninstalled along with other updates. "As soon as you run the Vsp1cln.exe tool, the Windows Vista SP1 package no longer appears in the Installed Updates list under Programs and Features in Control Panel. This tool works only with Windows Vista SP1, and it can be used online or offline," Microsoft added.
All you have to do in order to bundle SP1 with Vista RTM is to open an elevated command prompt. Just type cmd in the Search box under the Start menu and right-click the highlighted result choosing Run as Administrator from the contextual menu. Write the Vsp1cln.exe command and hit Enter. Now, you only have to choose between Yes and No.