diff --git a/confluent_server/confluent/shellserver.py b/confluent_server/confluent/shellserver.py
index f3633959..c6626227 100644
--- a/confluent_server/confluent/shellserver.py
+++ b/confluent_server/confluent/shellserver.py
@@ -37,7 +37,7 @@ class _ShellHandler(consoleserver.ConsoleHandler):
     def _got_disconnected(self):
         self.connectstate = 'closed'
         self._send_rcpts({'connectstate': self.connectstate})
-        for session in self.livesessions:
+        for session in list(self.livesessions):
             session.destroy()