[Samba] explorer.exe: no mapping between names and security ids was done

[Bernie Elbourn]

... I just want to put this somewhere easily searchable based on the users error message.

Upgrading a domain controller to Debian 8  (samba 3 to 4) resulted in the message "no mapping between names and security 
ids was done" at times. The message appears on the windows 7 domain pcs when running explorer.exe. Also other basic 
things did not work: internet explorer, or mapping between file types and extensions.  But only at times.

The problem is apparent when running set in a command on the affected windows pc. Look for the USERDOMAIN variable 
somewhere at the bottom of the list. It is not set to the real domain name. In my case it was the name of the server 
before it became a domain controller. I suspect the system was hanging together due to netbios names - eek. Mostly and 
for years running Debian 7, and samba 3 this was accidentally reliable.

A quick fix is possible on the samba domain controller:

sudo pdbedt -I "MYDOMAIN" -u username

.. the next login should return things to normal for the user.

 From the pdbedit manpage:

        -I|--domain
            This option can be used while adding or modifying a user account. It will specify the user's domain field.

            Example: -I "MYDOMAIN"

Hope this helps someone

Bernie

Ref: This hint - https://lists.samba.org/archive/samba/2005-December/115411.html from way back