Hi, Boost.Serialization has support for non-default classes using save_construct_data and load_construct_data overloads. These are called before serialization to save and load information that's important for the construction of the object. Unfortunately, multi_index doesn't call these functions when serializing, so serialization of non-default-constructible classes is impossible with multi_index. I wanted to patch it so that it becomes possible, but to be honest I'm a bit lost in the serialization code for multi_index. collections_save_impl calls boost::serialization::save_construct_data_adl before serializing each item in the collection. I'm using boost 1.38.0, is there anyway to do the same for multi_index? Thanks in advance, -- Felipe Magno de Almeida