diff --git management/univention-management-console/src/univention/management/console/protocol/server.py management/univention-management-console/src/univention/management/console/protocol/server.py
index f2d93ab840..ad8a21fa4d 100644
--- management/univention-management-console/src/univention/management/console/protocol/server.py
+++ management/univention-management-console/src/univention/management/console/protocol/server.py
@@ -36,6 +36,7 @@ Defines the basic class for an UMC server.
 """
 
 import os
+import gc
 import fcntl
 import socket
 import resource
@@ -80,7 +81,8 @@ class MagicBucket(object):
 		"""
 		CORE.info('Established connection: %s' % client)
 		state = State(client, socket)
-		state.session.signal_connect('success', notifier.Callback(self._response, state))
+		state.callback = notifier.Callback(self._response, state)
+		state.session.signal_connect('success', state.callback)
 		self.__states[socket] = state
 		notifier.socket_add(socket, self._receive)
 		self._timeout_connection(state)
@@ -102,8 +104,7 @@ class MagicBucket(object):
 		# remove all sockets
 		for sock in list(self.__states.keys()):
 			CORE.info('Shutting down connection %s' % sock)
-			self.__states.pop(sock).session.shutdown()
-			notifier.socket_remove(sock)
+			self._cleanup(sock)
 
 	def _receive(self, socket):
 		"""Signal callback: Handles incoming data. Processes SSL events
@@ -229,14 +230,14 @@ class MagicBucket(object):
 			self._cleanup(state.socket)
 
 	def _cleanup(self, socket):
-		if socket not in self.__states:
+		state = self.__states.pop(socket, None)
+		if state is None:
 			return
 
-		self.__states[socket].session.shutdown()
-
+		state.session.signal_disconnect('success', state.callback)
+		state.session.shutdown()
 		notifier.socket_remove(socket)
-		self.__states[socket].session.__del__()
-		del self.__states[socket]
+		state.session.__del__()
 
 		try:
 			socket.close()
@@ -406,6 +407,7 @@ class Server(signals.Provider):
 		categoryManager.load()
 		RESOURCES.info('Reloading UCR variables')
 		ucr.load()
+		gc.collect()  # Cleanup umcp.State objects
 
 
 class State(object):