We have a suite of components which offer the same set of interfaces. While investigating the possibility of client code using registration-free COM, we stumbled upon this problem. One client may use different implementations of the same inteface, depending on configuration provided by the user. Therefore, it must include a dependency for each one of these components. Each one of these components contains a comInterfaceProxyStub element registering the exported component interface. That is, we have many components with a comInterfaceProxyStub exporting the same set of interfaces, which they all implement. It seems this fact causes an error at activation time. ststrace.exe is not clear but it seems it is refusing to "register again". What are we missing? Is it supposed to be an error trying to activate a second component with a comInterfaceProxyStub element for an interface already "registered"?