The Microsoft "MSI" system leaves the original installation file laying around because it uses it for future upgrades. It never really "upgrades" anything. Instead, it completely uninstalls the current version and then fresh installs the new version. And the uninstall sometimes (often) fails to clean up all the old stuff. So there can be some useless build up. Thus, with Topaz, you have to download a 9+ GB file and suffer a complete uninstall and reinstall to apply a simple bug fix that could have been done with a 10K patch.