--- /usr/share/pyshared/univention/s4connector/s4/__init__.py.orig	2014-04-15 22:36:10.176000000 +0200
+++ /usr/share/pyshared/univention/s4connector/s4/__init__.py	2014-04-15 22:42:52.004000000 +0200
@@ -2314,7 +2314,8 @@
 								if value:
 									modlist.append((ldap.MOD_REPLACE, attr, value))
 								else:
-									modlist.append((ldap.MOD_DELETE, attr, None))
+									if s4_object.has_key(attr):
+										modlist.append((ldap.MOD_DELETE, attr, None))
 
 				ud.debug(ud.LDAP, ud.INFO, "to add: %s" % object['dn'])
 				ud.debug(ud.LDAP, ud.ALL, "sync_from_ucs: addlist: %s" % addlist)