ASUS RT-N66 - create_canon_ace_lists: unable to map SID

Hi there,
I am having a lot these messages in the log when I am trying to save on external hdd connected via samba.

Oct 22 00:46:39 smbd[12771]: [2015/10/22 00:46:39.272628, 0] smbd/posix_acls.c:1762(create_canon_ace_lists)
Oct 22 00:46:39 smbd[12771]: create_canon_ace_lists: unable to map SID S-1-5-21-96594065-3896462963-4078731193-1000 to uid or gid.
........

My environment:
Windows 7 Home Edition, ASUS RT-N66U on
Operation...

ASUS RT-N66 - create_canon_ace_lists: unable to map SID