Thak you BDAqua. Sadly I can't see my external drive as a device using the finder preferences as dicsussed in you link.
Finder > Preferences > General from the menubar and be sure the box forConnected Servers is checked.
Finder > Preferences > Sidebar and be sure the box for External Disks is checked.
Any other suggestions gratefully received.
Note, I am using a Time machine 2TB connected with an ethernet connector. I also have TM 2TB connected to a wireless router. I tried disconnecting the router connection from the 2TB and turning off my WiFi connection. Still no external drive idetified.