Hi all, I'm a relative newbie at using the serialization libraries, so please go easy on me, but I'm having some troubles which I can't seem to work out. I have a class hierarchy that looks something like this: A -> B -> C -> D There is a corresponding header, and at least one source file, for each of the four classes. The base class, A, contains only methods, but is not a pure virtual class. Class B contains the first set of data members in the chain that must be serialized. Classes C and D contain some more methods and data. All stores/loads will be handled via pointers to instances of class D. Now, the header file for class B contains the following: #include <boost/archive/text_iarchive.hpp> #include <boost/archive/text_oarchive.hpp> #include <boost/serialization/access.hpp> #include <boost/serialization/base_object.hpp> Classes B, C and D define the following as public: friend class boost::serialization::access; template<class Archive> void serialize(Archive &ar, const unsigned int version); The serialize methods for classes C and D call the base class implementations of these methods via: ar & boost::serialization::base_object<base_class>(*this); Finally, the source files for classes B, C and D contain: #include <boost/serialization/export.hpp> BOOST_CLASS_EXPORT(class_name); It's not clear to me, though, that I should need the EXPORT macro since all loads/stores are done with the most derived class' pointers. However, when I run this code, I get an exception at oserialization.hpp line 394, which is of type archive_exception::unregistered type. I've looked through a lot of the documentation, but can't seem to find out what I'm doing wrong. I've also tried explicit calls to boost::serialization::void_cast_register<base_class, derived_class> (), but that didn't seem to work either. Since this is being retrofitted to a large design, I tried to distill what I was trying to do into a sample project with just empty classes with the same hierarchy and boot methods/macros. When I do this, everything seems to work fine. Does anyone have any suggestions on what I should look for that may be screwing things up for me? I can send the sample files I used, but since these work, I'm not sure if they will be of much help. Any pointers will be greatly appreciated! Thanks, Joe