diff --git b/management/univention-directory-manager-modules/modules/univention/admin/handlers/__init__.py a/management/univention-directory-manager-modules/modules/univention/admin/handlers/__init__.py
index 1a78df5..8169f85 100644
--- b/management/univention-directory-manager-modules/modules/univention/admin/handlers/__init__.py
+++ a/management/univention-directory-manager-modules/modules/univention/admin/handlers/__init__.py
@@ -569,8 +569,7 @@ def __init__(self, co, lo, position, dn='', superordinate=None, attributes=None)
 			try:
 				self.oldattr = self.lo.get(self.dn, required=True)
 			except ldap.NO_SUCH_OBJECT:
-				pass
-#				raise univention.admin.uexceptions.noObject(self.dn)
+				raise univention.admin.uexceptions.noObject(self.dn)
 
 		if self.oldattr:
 			self._exists = True
diff --git a/base/univention-system-setup/umc/python/setup/netconf/modules/LdapNetwork.py b/base/univention-system-setup/umc/python/setup/netconf/modules/LdapNetwork.py
index edb4e88..c5015f2 100644
--- a/base/univention-system-setup/umc/python/setup/netconf/modules/LdapNetwork.py
+++ b/base/univention-system-setup/umc/python/setup/netconf/modules/LdapNetwork.py
@@ -3,7 +3,7 @@
 import univention.admin.objects
 import univention.admin.uldap as uldap
 import univention.admin.modules as modules
-from univention.admin.uexceptions import base as UniventionBaseException
+from univention.admin.uexceptions import base as UniventionBaseException, noObject
 from ldap import LDAPError
 
 
@@ -66,8 +66,9 @@ def _remove_old_network(self):
 		network_dn = "cn=default,cn=networks,%(ldap/base)s" % self.changeset.ucr
 		network_module = modules.get("networks/network")
 		modules.init(self.ldap, self.position, network_module)
-		network = univention.admin.objects.get(network_module, None, self.ldap, self.position, network_dn)
-		if not network.exists():
+		try:
+			network = univention.admin.objects.get(network_module, None, self.ldap, self.position, network_dn)
+		except noObject:
 			return
 		self.logger.info("Removing '%s'...", network_dn)
 		if not self.changeset.no_act: