PatchCleaner is designed to find orphaned and outdated installer files allowing you to easily delete them.When applications are installed and updated on your machine a hidden directory c:WindowsInstaller is employed to store .msi files and .msp files. These files are important during updating, patching or uninstalling software, during this process .msi/.msp files are used. Going click happy and deleting all the files contained in this folder may cause a serious issue that could result in the need for a total rebuild of the OS. PatchCleaner will help you identify these type of files and then provide you with the option to rid your system of them but not totally at first - you can place the selected files within a temp folder, better said an "are you sure you want to delete this" folder that will easily allow you to replace them to their original position if the removal causes any operating issues, etc.PatchCleaner identifies redundant/orphaned files and allows you to either: Move them to another location for safe keeping before the final removal - to play it safe Delete them