I had numerous problems managing user accounts with usrmgr.exe and the net rpc
group utilities (problems included being unable to modify the user due to group
errors, inability to edit some groups, and so forth). I tracked this down to a
group name of "Users", which appears to be reserved within Samba. Further
investigation showed that the "Administrators" group was also problematic.
I ass-u-me that there is some expectation that the Users and Administrators
groups are going to be local/built-in groups (they exist in all NT domains).
However, this is not a particularly valid assumption for Samba, since *NIX does
not really have an applicable concept of "local" groups (nesting isn't
applicable and doesn't mean anything, for example).
I have posted a series of screenies at http://www.ehsco.com/misc/samba/ and some
discussion on this problem can also be seen in the list archives at
The correct fix will does in fact implement the BUILTIN groups
will be in a future release. The assumption about Users
and Administrators is valid, even in Samba.