Hello Robert, I found a way to avoid the link problem when dealing with a base abstract class, that maintains the base class abstract : I just manually instantiated the save/load functions for the abstract base class. They should have been instantiated by BOOST_CLASS_EXPORT, but this apparently does not work with abstract base classes; however manual instantiation works just fine. So I now have only one more problem (unfortunately, very serious), that happens with the serialization of std::vector containing pointers. Jean-Noël