<p style="text-align: left;">Yes, I understand that. I am sorry I should have been more clear; the base class is abstract. I am able to get the "unregistered class" exception in test_no_rtti.cpp, in load_derived, by removing the serializations using derived class pointers (which register the classes). When execution tries to serialize using the base class pointer, the "unregistered class" exception is thrown. I expect this to not happen because all the classes are registered using BOOST_CLASS_EXPORT. Could BOOST_CLASS_EXPORT not be working? Do you see this when commenting out the derived class serializations in load_derived?</p> <p style="text-align: left;">Thanks,</p><p style="text-align: left;">Daniel Roberts<br></p><p style="text-align: left;"><br></p><p style="text-align: left;">Only polymophic types can be serialized through a base class pointer. <br> </p>Robert Ramey