There is no "Download Now" button on the Microsoft website for this file. The official and only way to obtain it is to have Microsoft Excel (part of the Office suite) properly installed on your machine. This is by design; the type library is tightly integrated with the Excel application.
Developers frequently encounter the when automating Excel tasks through external applications. This library serves as the vital bridge between programming languages like VBA, C#, or VB.NET and the Excel application interface.
If you are writing macros in VBA and get the "User-defined type not defined" error, follow these steps: Press ALT + F11 inside Excel to open the VBA Editor. Click on in the top menu bar and select References .