I know that recently some changes have been made to the serialization library to make it raise exceptions on error rather than fail assertions. In particular, at line #300 of boost/serialization/oserializer.hpp an unregistered_class exception is now thrown when the type information system hasn't heard of the class which is to be serialized. I think we could go further to aid debugging if the archive_exception class had another data member which could be used to store the name of the class which couldn't be written. We'd have something like this instead... boost::throw_exception( boost::archive::archive_exception( boost::archive::archive_exception::unregistered_class, typeid(*(&t)).name() // THIS IS THE NEW BIT ) ); When catching the exception what() would be able to return "unregistered class: my_derived_class" rather than just "unregistered class". When you've got a few dozen different classes to serialize through pointers to base classes it would make it a lot easier to find out which one you haven't registered properly. Of course, this does assume that RTTI is available on all our platforms. Is that an assumption we can make? If not, could we revert to the current behaviour on platforms which don't have it? Do the other users of the serialization library have a strong point of view on this? DT