Windows contains a hidden directory at C:\Windows\Installer that stores install and patch files for many applications. Over time this directory can become quite bloated with redundant and orphaned files. I have seen some computers with over 20 GB of installer data that can be deleted, so this is a great directory to clean up in order to save disk space.
It isn’t safe to delete the entire Installer directory since applications may reference these files when installing, updating, and uninstalling, but there are proper ways to unclutter it.
The folks over at homedev have created a fantastic tool called PatchCleaner that examines the Windows installer directory and optimizes it. PatchCleaner can be downloaded from homedev’s website here: http://www.homedev.com.au/free/patchcleaner
Once installed and ran, the program will scan your Windows installer directory. It will identify how many files are still needed, how many are excluded due to filters, and how many are orphaned:
Simply choose if you wish to delete or move the orphaned files. Thanks, homedev!