Index: deluge/core/signalmanager.py
===================================================================
--- deluge/core/signalmanager.py        (revision 2755)
+++ deluge/core/signalmanager.py        (working copy)
@@ -66,6 +66,8 @@
             gobject.idle_add(self._emit, uri, signal, 1, *data)

     def _emit(self, uri, signal, count, *data):
+        if uri not in self.clients:
+            return
         client = self.clients[uri]
         try:
             client.emit_signal(signal, *data)