Problem: After a ldap schema was removed, there are still some references in your ldap

Problem:

After a ldap schema was removed (based on this article), there are still some references in your ldap
You find the follwing message, when you use slapindex or slaptest.

~# slapindex
WARNING!
Runnig as root!
There's a fair chance slapd will fail to start.
Check file permissions!

5cade2d2 UNKNOWN attributeDescription "OWNCLOUDENABLED" inserted.
5cade2d2 UNKNOWN attributeDescription "OWNCLOUDQUOTA" inserted.

Solution:

You need to find the references and reload the ldap.
Attention! In large environments this my take a lot of time.

root@ucs:~# mkdir ldap-backup 
root@ucs:~# cd ldap-backup 
root@ucs:~/ldap-backup# /etc/init.d/slapd stop 
root@ucs:~/ldap-backup# slapcat > backup.ldif

You have to edit the backup.ldif and remove the references to the above attributes (i.e.
OWNCLOUDQUOTA) in the backup.ldif

root@ucs:~# cd
root@ucs:~# mkdir DB
root@ucs:~# mv /var/lib/univention-ldap/ldap/* DB/
root@ucs:~# ucr commit /var/lib/univention-ldap/ldap/DB_CONFIG 
root@ucs:~# slapadd < ldap-backup/backup.ldif 
root@ucs:~# /etc/init.d/slapd start