none of the overload functions were introduced by 'interface'
You tried to explicitly override a member that does not exist in the specified interface. For example:
#pragma warning(disable:4199) __interface IX14A { void g(); }; __interface IX14B { void f(); void f(int); }; class CX14 : public IX14A, public IX14B { public: void IX14A::g(); void IX14B::f(); void IX14B::f(int); }; void CX14::IX14A::f() // Error C3243 occurs here { }