When using a stringstream in binary mode along with the non-portable binary archive occasionally I see the serialization code throw bad_alloc when reconstructing an object. It appears to be when trying to serialize a derived stl map. We derive from std::map in our project to add a few more convenience methods and a simpler interface and I then added the following code to serialize this newly derived type: template<class Archive> void serialize(Archive &p_archiver, foobar::ResourceMap &p_map, const unsigned int version) { p_archiver & base_object<map<foobar::ResourceMap::key_type, foobar::ResourceMap::mapped_type> >(p_map); } I assume that is OK? It appears to work most of the time. Could it be that when that map is empty it encounters odd behaviour? I pass, to the archive constructor, the no_header flag - is this a problem? I haven't tried the text archivers yet. This is with Boost version 1.35 on an x86-64 Linux installation (gcc 4.1.2) . I get the same behaviour with and without optimisation (-O0 -g3 and -g0 -Os) and with an unlimited stack size and a limit of ~10M. Has anyone else seen similar behaviour. Using a hash function (SHA1) I can see that the same bytes that make up these messages (in our protocol classes are serialized in the payload of messages) are sent to and from the peers so I am pretty sure (though not 100% yet) it isn't due to any corrupt or incorrect data in the underlying stringstreams (the string streams are essentially made up of the message payload) themselves. Regards, Jim Vanns -- James Vanns Systems Programmer Framestore CFC Ltd.