Comment 0 for bug 1583324

Samba refuses to start when the smb.conf file contains an include line with a variable substitution like "include = /etc/samba/smb.conf.%U"

According to the man page for smb.conf, all but a few specific variable substitutions should work.

include (G)

           This allows you to include one config file inside another. The file is included literally, as though typed in place.

           It takes the standard substitutions, except %u, %P and %S.

           The parameter include = registry has a special meaning: It does not include a file named registry from the current working directory, but
           instead reads the global configuration options from the registry. See the section on registry-based configuration for details. Note that
           this option automatically activates registry shares.

           Default: include =

           Example: include = /usr/local/samba/lib/admin_smb.conf

It is probably related to this bug in samba:
https://bugzilla.samba.org/show_bug.cgi?id=10722

Description: Ubuntu 16.04 LTS
Release: 16.04

samba:
  Installed: 2:4.3.9+dfsg-0ubuntu0.16.04.1
  Candidate: 2:4.3.9+dfsg-0ubuntu0.16.04.1
  Version table:
 *** 2:4.3.9+dfsg-0ubuntu0.16.04.1 500
        500 http://us.archive.ubuntu.com/ubuntu xenial-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu xenial-security/main amd64 Packages
        100 /var/lib/dpkg/status
     2:4.3.8+dfsg-0ubuntu1 500
        500 http://us.archive.ubuntu.com/ubuntu xenial/main amd64 Packages