Hello, I am boost-serializing some instances of polymorphic class using their base class pointer. I get the 'archive_exception::unregistered_cast' exception at runtime when serializing one of them. The comment at line 407 of oserializer.hpp (where the exception is thrown) "convert pointer to more derived type. if this is thrown it means that the base/derived relationship hasn't be registered". The code is here below. I think i registered correctly the derived classes, but I have not been able to make it working: in few words, i cannot serialize a Serializable class using a pointer to its base SerializableBase base class. Any suggestion? TIA, Luca using namespace std; using namespace boost; using namespace boost::serialization; struct SerializableBase { virtual ~SerializableBase () { } template<typename Archive> void serialize (Archive& pAR, unsigned int version) { int i (0); pAR & make_nvp ("doesnotwork", i); } }; struct Serializable : public SerializableBase { int a; Serializable () : a (1) { } virtual ~Serializable () { } template<typename Archive> void serialize (Archive& pAR, unsigned int version) { pAR & BOOST_SERIALIZATION_NVP (a); pAR & make_nvp ("woowoo", b); } };//struct void save (const Serializable& pS, const char* pFileName) { // make an archive std::ofstream ofs (pFileName); boost::archive::xml_oarchive oa (ofs); // Registering a lot of things here! oa.register_type (static_cast<Serializable*> (NULL)); oa.register_type (static_cast<SerializableBase*> (NULL)); oa.register_type<shared_ptr<SerializableBase> > (); oa.register_type<shared_ptr<Serializable> > (); oa.register_type<Serializable> (); oa.register_type<SerializableBase> (); SerializableBase* lS (new Serializable); oa << make_nvp ("lS", lS); } int main () { Serializable s; save (s, "serializable.xml"); }