Various embodiments of the present invention are directed to systems and methods for synchronizing mixed elements (MEs) comprising structure data and unstructured filestreams between peer computer systems in a hardware/software interface system environment that does not permit snapshotting of large unstructured ME filestreams during synchronization. For several such embodiments, the method comprises synchronizing the ME in two steps, one for snapshotting the structured data component of the ME (as well as the cv of the filestream but not the filestream itself) and one for locking and transmitting the filestream to the receiving sync peer if and only if, after being locked, it is determined that the filestream is unchanged from the time of the ME data component snapshot.