Hi, Samba 4.0.9 on CentOS 6.4 serving Windows XP clients here. I still haven't sat down and figured out Windows-RID-to-unix-ID maps yet. However, I noticed that I can put a person's lowercased name in a 'valid users' list for a share and it works, even though they don't have a unix account. But doing this for lowercased custom group names (we have a 'MYDOM\Supervisors' group, so I tried @supervisors or supervisors) didn't seem to have any effect. Why is that? I also tried to figure out the unix ID that that group maps to by taking a test file in Windows and going to the Advanced part of security and changing the owner to MYDOM\Supervisors. In ls -l on CentOS it shows up as 3000014. So I tried 3000014 with or without @ in front of it in 'valid users' for a share, but to no effect. That I understand even less. :) Thanks for any illumination here, Kev