+1 Client is osx 10.11.4 El Capitan
server log: [2016/04/22 01:35:57.524851, 2] ../source3/param/loadparm.c:2596(lp_do_section) Processing section "[bigdrive]" [2016/04/22 01:35:57.530698, 3] ../source3/auth/auth.c:178(auth_check_ntlm_password) check_ntlm_password: Checking password for unmapped user []\[GUEST]@[TYRELL] with the new password interface [2016/04/22 01:35:57.530891, 3] ../source3/auth/auth.c:181(auth_check_ntlm_password) check_ntlm_password: mapped user is: [BIGDRIVE]\[GUEST]@[TYRELL] [2016/04/22 01:35:57.531198, 3] ../source3/auth/check_samsec.c:400(check_sam_security) check_sam_security: Couldn't find user 'GUEST' in passdb. [2016/04/22 01:35:57.531340, 2] ../source3/auth/auth.c:315(auth_check_ntlm_password) check_ntlm_password: Authentication for user [GUEST] -> [GUEST] FAILED with error NT_STATUS_NO_SUCH_USER [2016/04/22 01:35:57.531758, 3] ../source3/auth/auth_util.c:1599(do_map_to_guest_server_info) No such user GUEST [] - using guest account [2016/04/22 01:35:57.531973, 1] ../auth/ntlmssp/ntlmssp_server.c:908(ntlmssp_server_postauth) ntlmssp_server_postauth: invalid NTLMSSP_MIC for user=[GUEST] domain=[] workstation=[TYRELL] [2016/04/22 01:35:57.532099, 1] ../lib/util/util.c:559(dump_data) [0000] 13 8D 02 4D 77 E3 5C F0 B4 D3 1C 19 1C CA 5B 3D ...Mw.\. ......[= [2016/04/22 01:35:57.532391, 1] ../lib/util/util.c:559(dump_data) [0000] FC 6D 76 6D 22 0C 30 69 43 75 0F 14 DD 80 17 76 .mvm".0i Cu.....v [2016/04/22 01:35:57.532677, 2] ../auth/gensec/spnego.c:708(gensec_spnego_server_negTokenTarg) SPNEGO login failed: NT_STATUS_INVALID_PARAMETER full smb.conf is: [global] workgroup = WORKGROUP smb ports = 445 139 guest account = nobody log level = 2 auth:3 server string = bigdrive security = user map to guest = Bad User log file = /var/log/samba/%m.log max log size = 50 dns proxy = no [bigdrive] path = /mnt/share public = yes only guest = yes writable = yes root@bigdrive:/var/log/samba# smbd -V Version 4.2.10-Debian root@bigdrive:/var/log/samba# uname -a Linux bigdrive 4.1.19-v7+ #858 SMP Tue Mar 15 15:56:00 GMT 2016 armv7l GNU/Linux -jp -- Jeffrey Paul EEQJ j...@eeqj.com https://eeqj.com +1-800-403-1126 (America) +1-312-361-0355 (Worldwide) 5539 AD00 DE4C 42F3 AFE1 1575 0524 43F4 DF2A 55C2