[This is preliminary documentation and subject to change.]
Best Practice (Designed for Microsoft® Windows® Logo)
If your installer finds a shared component already on the system and not registered, the SharedDLL reference count should be incremented by one plus the number of clients being installed.
For example, if you install your application with three clients using a shared component, your installer will raise the SharedDLL count by three. But if the shared component is already on the system and no SharedDLL exists for it (that is, the previous installer did not create the ref-count), set the SharedDLL count to four. This way, when your application is uninstalled, it leaves the shared component on the system with a ref-count of one.