Hi, I encountered the following little problem: I would like to use the following datastructures with boost::serialize: struct Match {}; typedef std::string Key; typedef tst< Match, Key > TernarySearchTree; //this one has a shared_ptr typedef std::vector< TernarySearchTree > Trees; typedef std::map< std::string, Trees > Symbols; I have defined some serialize overloads so saving goes fine, but when loading I get a "memory acces violation" inside the following code: { boost::archive::text_iarchive ia(ifs); ia >> symbols_; } More specific, inside <boost/serializiton/shared_count.hpp> void add_ref_copy() { #if defined(BOOST_HAS_THREADS) mutex_type::scoped_lock lock(mtx_); #endif ++use_count_; } Which constructs a scoped_lock, and there, the "explicit scoped_lock(lightweight_mutex & m): m_(m)" seems to go wrong. What could be the reason? The more since all worked fine (saving and loading) when I used a simple vector of tst's. Is it not possible to use a map of string/vector (the error seems to suggest the library failing when copying vector to map - eg ++use_count of the shared_ptr inside the TST). Thanks in advance, Dirk