Shared DLLs

If an application uses a common or shared DLL it must increase the usage counter of that DLL in the Registry. During uninstallation, the application must decrease the usage counter of a common or shared DLL. Most of the time, shared DLLs are located in the Windows subdirectories, such as System and System32. Large suites of applications are prime candidates to have shared DLLs that are not located in the Windows subdirectories. For example, the DLLs for the spell checking in the Microsoft Office suite are located in the Common Files subdirectory of Microsoft Office. Sometimes, obsolete DLLs remain on your hard drive and with a positive usage counter in the Registry even if all the applications that used them have been uninstalled. You can set the usage counter of this DLL to zero by editing the Registry directly.

Editing the Registry should be done only by experienced users and with extreme care and the Registry should always be exported or backed up before any changes are made.

1. Start the REGEDIT.EXE program.

2. Go to the key HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\Current Version\SharedDLLs

3. A list of all the shared DLLs with the full path to the location where they are stored on your hard disk and with their usage counter is displayed. Double click on the name of the obsolete DLL and set its value to zero.