Do not use the existing UNIX print system spool directory for the Samba spool directory. It may seem convenient and a savings of space, but it only leads to problems. The two must be separate. The UNIX/Linux system print spool directory (e.g., /var/spool/cups) is typically owned by a non-privileged user such as cups or lp. Additionally. the permissions on the spool directory are typically restrictive to the owner and/or group. On the other hand, the Samba spool directory must be world writable, and should have the 't' bit set to ensure that only a temporary spool file owner can change or delete the file.

Depending on the type of print spooling system in use on the UNIX/Linux host, files that the spool management application finds and that are not currently part of job queue that it is managing can be deleted. This may explain the observation that jobs are spooled (by Samba) into this directory and just disappear.