sudo apt-get install -f
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
1 not fully installed or removed.
After this operation, 0 B of additional disk space will be used.
Setting up samba4 (4.0.0~alpha17~git20110807.dfsg1-1ubuntu1) ...
Administrator password will be set randomly!
ProvisioningError: guess_names: 'realm =' was not specified in supplied /etc/samba/smb.conf.  Please remove the smb.conf file and let provision generate it
dpkg: error processing samba4 (--configure):
 subprocess installed post-installation script returned error exit status 1
Errors were encountered while processing:
 samba4
E: Sub-process /usr/bin/dpkg returned an error code (1)