Pierangelo, back-sql fails to compile with BACKSQL_TRACE defined, I think this is the correct fix. It also appears that objectClass searches fail (with mysql odbc) if there is no data in the ldap_entry_objclasses table. Just a simple dummy entry like this is enough to fix the problem. +----------+----------+ | entry_id | oc_name | +----------+----------+ | 0 | dcObject | +----------+----------+ Let me know if you'd like more information. I believe this is the issue noted here... http://www.openldap.org/lists/openldap-software/200508/msg00450.html Regards, Rob -- Robert Brooks, Network Manager, Cable & Wireless UK <robb(a)wtg.cw.com&gt; http://wtg.cw.com/ Tel: +44 (0)20 7339 8600 Fax: +44 (0)20 7339 8601 - "What was your username again?" - BOFH -