Thanks to Andreas and Martijn for your help. I had already your suggestions but it wasn't working. However, I have now been able to upgrade to Five v1.4.2 (rather than v1.4.4) by simply un-taring it in the Plone products directory - you both suggested. It seems Five v1.4.4 is faulty. When I untar it in the Plone products directory and attempt to restart the Zope client, the zeoserver.log reports: " ... (4713) new connection ('127.0.0.1', 54709): <ManagedServerConnection ('127.0.0.1', 54709)> (127.0.0.1:54709) received handshake 'Z303' (4713/127.0.0.1:54709) disconnected (4713) new connection ('127.0.0.1', 54711): <ManagedServerConnection ('127.0.0.1', 54711)> (127.0.0.1:54711) received handshake 'Z303' (4713/127.0.0.1:54711) disconnected (4713) new connection ('127.0.0.1', 54712): <ManagedServerConnection ('127.0.0.1', 54712)> (127.0.0.1:54712) received handshake 'Z303' (4713/127.0.0.1:54712) disconnected ... " every few seconds. Still, my problem seems to be solved since Reflecto v1.2 only requires Five v1.4.1 or higher. Thanks James