My Play 1 seems to have a serial number of: 1311-00-0E-58-CD-D3-76-A
My mac is running the current OS satisfactorily, I have plenty of RAM etc.
Best answer by ratty
If the PLAY:1 is not appearing in the controller and jgatie's suggestion doesn't help then, given that the system hasn't been used in an age, and unless you have cherished Sonos Playlists stored, you might as well reset everything and start again. Reset a Player by powering it up whilst holding down the Play/Pause (formerly Mute) button until the LED flashes amber, then release and wait for green. Reset the controller(s) in Advanced Settings.