It started when I was following the FDS instructions for setting up Samba. Having religiously followed every step, I got to the bit about setting up the Administrator account:
# smbpasswd -a Administrator -w
Setting stored password for "cn=Directory Manager" in secrets.tdb
Was that right? I suspect not. What I've discovered is that if I replace "Administrator" here with any account name - including no name at all - I get the same result!
The next step was where it really went wrong. This is supposed to modify the Samba Administrator account to use the correct SID (one ending in a RID of 500):
# pdbedit -U $( net getlocalsid sed 's/SID for domain RIVERSIDE is: //' )-500 -u Administrator -r
All I get is:
Username not found!
The final step in the instructions is to test creating a new user:
# smbpasswd -a testuser
Which just returns:
Failed to modify password entry for user testuser
I've done a lot of googling on this. There are plenty of reports of this sort of error, but precious few answers.