If you have ever used MSI installation packages involving Windows Installer, you are probably aware of its nuisance. I can deal with the fact that it's a pain to create decent installations without shelling out hundreds or thousands of dollars for third party tools such as Wise and InstallShield, but I just can't cope up with the fact that my customers can't install or uninstall an application built using Windows Installer for no apparent reason. When using the Add/Remove Programs applet in the Control Panel, sometimes MSI packages can't be removed. I have a system with BizTalk Server installation that I can't get rid of. There are even issues around upgrading an application and at times the installer complains and won't budge.
To alleviate some of the pain, Microsoft finally came up with a Windows Installer Cleanup Utility, that can be used to remove all references to a given application from your system. This utility just saved me a few hours worth of work when Installer refused to uninstall a given application from my system so that I could install a newer version. Without this utility I would have had to go through and search my registry for all references to the application and remove them by manually hand. Then, if I was lucky, I would be allowed to install the newer version of the application. With this utility I removed the application from my system in seconds and painlessly installed the newer version after that.