Login not possible after update to UCS5.2-3 on school slaves, caused by an nearly empty samba database.
Investigation
If we face login problems, we should first check for users and computers being present in ldap AND samba. The authentication is always based on kerberos, which in most cases is serverd by samba. (If you do not have samba4 installed we use heimdal for kerberos, and this article is not suitable)
Solution:
You can run univention-join
or
reinitialize the s4connector to get all objects from ucs into samba again:
or
A similar problem with an other soultion is described here: