I had a major version upgrade to a mission critical system involving a multi-server architecture recently. One of the component upgrades failed because the previous version of the application would not uninstall properly.
The only reason that I knew this was because of the log file that was generated by the upgrade itself. But once I knew the cause I also knew that I had a tool to use.
I’ve used these “Fix It” tools from Microsoft off and on over the years. I’ve always thought they were useful when available. This particular one is really neat. When you run it on a localhost, you can see programs that are installed and analyze them for uninstall issues for a variety of reasons. Once the analysis is complete, you can use the tool to perform the uninstall. Very handy!