Why do I get E_NOINTERFACE when creating an object that supports that interface?
I've seen a few questions from people who call
the CoCreateInstance function,
asking for an interface that they know the object supports,
yet receiving error E_NOINTERFACE.
What's going on?
You're seeing
the same problem as the missing IMarshal,
just from the other side.
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.
A common source of this is attempting to use COM objects provided
by the shell from a multi-threaded apartment. Remember that shell
COM objects are, for the most part, apartment-threaded, not
free-threaded.
If you want to use shell objects, you should do so from single-threaded
apartments.
