We all know that when we use COM interop with .NET we get some RCW (Runtime Callable Wrapper) CLR object representing and controlling access to the underlying COM object. When we call the C# new operator, under the hood the RCW calls the CoCreateInstance API to create the actual COM object, etc. What may not be apparent, is that there may exist another proxy to the COM object, even if the COM server is a DLL (in-process server). The reason this may happen is related to COM apartments. an Apartment...