Hello All, I have investigated the issue little bit more. I have observed the following: The code works properly after shifting of ~OrdBasis() definition into the source code. Hence, I suppose that compiler suite of MVSC 11.0 ignores in fact the results of A.CPP file. The result is obvious. Registration by BOOST_CLASS_EXPORT_IMPLEMENT(Ord<Options>) is not done. The same behavior was reproduced with MSVC 10.0 (Visual Studio 2010). Curiously, the situation depends on the code that is shifted to the source code file. The shifting of the Option class constructor in to the source code is not sufficient. Could anyone, please, check the behavior with other compilers. Is it a compiler suite (linker or compiler) bug? Or the problem with boost implementation? Kind Regards,