A colleague of mine ran into a problem testing a .net component (the server component). The underlying problem was that the .net component was deriving from Enterprise Services, i.e. it behaves like a COM+ component. I believe the issue here is that the profiler style interception used by TypeMock does not prevent the COM+ interception and therefore the "normal" code for server component runs rather than the mocked code. I’ve not looked into a solution for that yet as the COM+ code is only a thin wrapper to other non-COM+ code so we decided to simply not mock it.