There is a new general-purpose installation troubleshooting tool called the Windows Installer Cache Verifier Package troubleshooter that has been available on the Microsoft support site for a little while, and I want to post some information about this tool to help make it easier for people to find it.
The Windows Installer Cache Verifier Package troubleshooter is integrated into the Microsoft Support Diagnostics service. It can be used to detect if any .msi or .msp files are missing from the Windows Installer cache on a computer (typically located at c:\windows\installer). If any files are missing, it will identify what products are associated with the missing files.
Missing files in the Windows Installer cache is a common cause of problems encountered when trying to uninstall, repair or update MSI-based products. If you run the Windows Installer Cache Verifier Package troubleshooter and it reports problems, there are some recovery options listed in the tool’s knowledge base article.