The System Update Readiness Tool for Windows Vista was initially made available in mid-April 2008, following the release of Service Pack 1. Earlier this week, the Redmond giant delivered an update version of the tool, focused only on the 32-bit editions of the latest Windows client. Also up for grabs, the System Update Readiness Tool for x64 based systems remains as it was back in April 2008, and is limited to just the RTM SKUs of Windows Vista. By contrast, System Update Readiness Tool for Windows Vista (KB947821) has evolved to also encompass Vista SP1.

Microsoft explained that the necessity of the tool was catalyzed by what it referred to as inconsistencies in the Windows servicing store. Such problems would automatically lead to scenarios in which end users would find it impossible to install software on the operating system. Additionally, the Windows servicing store issues could also impact the ability of the platform to detect, download and deploy updates and service packs.

"After you download the System Update Readiness Tool, it runs a onetime scan for inconsistencies that might prevent future servicing operations. This scan typically takes less than 15 minutes to run. However, the tool might take significantly longer on some computers. The Windows Update progress bar is not updated during the scan, and progress seems to stop at 60% complete for some time. This behavior is expected. The scan is still running and you should not cancel the update," Microsoft explained.

Essentially the System Update Readiness Tool is designed to provide fixes for any of the inconsistencies detected in the Windows servicing store, and to return the operating system to normal. The tool will analyze in-memory data, registry data and file data for any issues that could prevent a "healthy" updating process for Windows Vista.

System Update Readiness Tool for Windows Vista is available for download here.