diff --git a/shell/PresenceService/PresenceService.py b/shell/PresenceService/PresenceService.py
index f062a830..72e9460a 100644
--- a/shell/PresenceService/PresenceService.py
+++ b/shell/PresenceService/PresenceService.py
@@ -265,7 +265,13 @@ class PresenceService(object):
 		self._bus_name = dbus.service.BusName(_PRESENCE_SERVICE, bus=self._session_bus)		
 		self._dbus_helper = PresenceServiceDBusHelper(self, self._bus_name)
 
+		self._started = False
+
 	def start(self):
+		if self._started:
+			return
+		self._started = True
+
 		# Connect to Avahi for mDNS stuff
 		self._system_bus = dbus.SystemBus()
 		self._mdns_service = dbus.Interface(self._system_bus.get_object(avahi.DBUS_NAME,