Hi there, I have a dll that contain an abstract base class called DbObject and a DbDatabase class that contains a collection of shared_ptr<DbObject> . It dose work as long all derived classes are defined in the same dll. With a class derived from DbObject and defined/implemented in my EXE (that use the DLL) I got archive_exception::unregistered_class. I tried to register it or to export it, but I could not make it work. Any Ideas? I use Version 1.38 of the library & VC8(2005). When I use BOOST_CLASS_TYPE_INFO(as in test_no_rtti.cpp sample ) for my EXE resident class, the ::get_key is never called. // get the eti record for the exported type "polymorphic_derived2" boost::serialization::extended_type_info const * const d2_eti = boost::serialization::extended_type_info::find( "polymorphic_derived2" ); works too before I start to serialize the collection. Thanks, Andrei _________________________________________________________________ Show them the way! Add maps and directions to your party invites. http://www.microsoft.com/windows/windowslive/products/events.aspx