– Terminate applications that use MDAC:
– Certificate Server
– Internet Explorer
– Internet Information Server
– Microsoft Office
– Outlook and Outlook Express
– SQL Server
– SMS Server
– Visual Studio (All Products)
– MDAC setup installs new data access DLLs and updates DLLs which already exist on the system.
– If one or more of those DLLs is in use by some other application, it can lead to unsuccessful MDAC setup.
– Some applications that use MDAC DLLs run in the background, so sometimes the user is not aware of their existence.