@@ -1169,14 +1169,16 @@ def _build_attr_header(local_list, src):

             except KeyError:

                 attr = "uid"

                 val = local_list[src].get('uid')

-                warning(u"%s: Owner username not known. Storing UID=%d instead." % (src, val))

+                if val:

+                    warning(u"%s: Owner username not known. Storing UID=%d instead." % (src, val))

         elif attr == 'gname':

             try:

                 val = Utils.getgrgid_grpname(local_list[src].get('gid'))

             except KeyError:

                 attr = "gid"

                 val = local_list[src].get('gid')

-                warning(u"%s: Owner groupname not known. Storing GID=%d instead." % (src, val))

+                if val:

+                    warning(u"%s: Owner groupname not known. Storing GID=%d instead." % (src, val))

         elif attr == 'md5':

             try:

                 val = local_list.get_md5(src)