When you click the Registry icon you will see all the available Registry rules that CCleaner can clean.
Missing Shared DLLs - Removes entries for libraries which are shared by multiple programs but no longer exist.
Unused File Extensions - Removes entries for file extensions that are no longer associated with applications.
ActiveX and Class Issues - Removes invalid entries for COM/ActiveX object that refer to a non-existing files.
Type Libraries - Removes invalid entries for type libraries that refer to non-existing files.
Applications - Removes invalid entries for non-existent programs.
Fonts - Removes invalid entries for fonts that no longer exist in the Windows Fonts folder.
Application Paths - Removes entries for registered application paths that no longer exist.
Help Files - Removes entries referring to help files that no longer exist.
Installer - Removes unnecessary uninstallers or the remnants of left over uninstallations.
Obsolete Software - Removes entries for applications that are no longer installed.
Run At Startup - Removes entries for Startup applications that no longer exist.
Start Menu Ordering - Removes entries for Start menu application that no longer exist.
MUI Cache - Removes invalid entries from a cache of recently run programs.
Sound Events - Removes references to sound files that do not exist.
Windows Services - Removes Windows Services, for which the executables are no longer present.
