I have excel with the Bloomberg API ( which uses simple calls like =BDP("MS equity","ask") ). I also have a C# application that opens an excel file (through interop) that uses the Bloomberg API. I have read [here](https://stackoverflow.com/questions/1154558/how-to-load-an-excel-addin-using-interop) that addins are not loaded when you load excel through interop. I have even tried using the code suggested there. However, that only seems to work for XLL and XLAM files and it looks like Bloomberg also uses DLL files which doesn't get loaded. Is there any way to get all of these addins to be loaded through interop?