Hello, wouldn't it be suitable to add serialasation support to boost::guid? regards, Oliver #include <boost/serialization/split_member.hpp> class BOOST_GUID_DECL guid : public boost::totally_ordered< guid > { private: ... friend class boost::serialization::access; template< class Archive > void save( Archive & ar, const unsigned int version) const { std::string str = to_string(); ar & str; } template< class Archive > void load( Archive & ar, const unsigned int version) { std::string str; ar & str; construct( str); } BOOST_SERIALIZATION_SPLIT_MEMBER(); ... };