Ran into a case yesterday where a client had Adobe CS5.5 but also had CS3. I used the installer to uninstall CS3 as they haven’t used it for years. Problem is, that also uninstalls things in common folders that the new version still uses. Huge mistake by Adobe, but there it is. It deleted all of the Adobe PDF presets, and also the Adobe Unit Types file from the Scripting Additions folder in the Library. This one is a particular problem because it prevents Photoshop from launching. So I won’t be doing this anymore! Yes it’s tidier to have only the version of CS that they use, but uninstalling causes too many unknown headaches and panicked calls.