CoCreateInstance returning E_NOINTERFACE even though interface is found

Question

I have a COM class CMyCOMServer implementing IMyInterface in one application, both with correct GUIDs. CMyCOMServer::QueryInterface wi

Answer 1

Could this be the threading model problem that Raymond Chen wrote about?

Edit in reply to the comment:

If your threading model is incompatible with the threading model of the object you're creating, then COM marshalling kicks in. And if the marshalling stuff isn't there, the error that comes out is E_NOINTERFACE, because the marshalling interface is missing.

It's more about threading models than about marshalling, really.