Why Doesn't the Uninstall Process Uninstall Some Files and Folders?

Have you ever wondered why Add/Remove Programs doesn't remove everything you think it should? WiseUser enlightens us with these answers to a few questions from the "mysteries of life" folder.

There are four common reasons for why files may not be removed during uninstallation:

• The components to which these files belong are marked as permanent. (This is done through the Attributes column of the Component table.)
• None of the components to which these files belong have component GUIDs. (The value for the component in the ComponentId column of the Component table is NULL). Components without GUIDs are not managed by Windows Installer.
• If the keypath of the component has a shared DLL refcount, then the component will not be uninstalled.
• If the component is installed in the system folder and at the time of uninstallation there is an external shared DLL refcount for any one file in the component, then the component will not be uninstalled.

Folders are not removed during uninstallation because of one of the following reasons:

• The RemoveFolders action is missing from the execute sequence table when both the CreateFolder table and CreateFolders action are used.
• The folders were not created by Windows Installer, therefore it will not remove them unless told to do so.
• Resources still exist in the folder.