In this post, you’ll learn about the error “CO_E_NOT_SUPPORTED 0x80004021” that is returned when working with COM based APIs or libraries in Windows.
COM Error Message
What is COM?
Microsoft’s COM stands for Component Object Model. Component Object Model (COM) is a networked, object-oriented framework for building interoperable binary software components. Microsoft’s OLE (compound documents), ActiveX (Internet-enabled components), and other products are built on the COM base technology.
Below is the description of this COM Error.
The operation attempted is not supported.