Yup - I found it...
Not surprisingly it was something I did (or maybe not).
My Spec-assembly was in .NET 4.0 and hence could not be loaded by the
SpecFlow.exe-project that is in .NET Framework 3.5.
I changed it now in a local copy and it works just fine.
Is there a reason not to upgrade all projects to 4.0? If you create
MsTest projects with Visual Studio 2010 you (until recently) had to
I can live with my local copy for now but other people might run into
the same issue, I presume