nmbd/nmbd.c: if (!pwdb_initialise(False)) { exit(1); } lib/util_pwdb.c: BOOL pwdb_initialise(BOOL is_server) { ... if (is_server) { ... (local file access) } else { if (!get_domain_sids(&global_member_sid, &global_sam_sid, global_myname)) { return False; } } What about file locking?