Afterthoughts. By cross-checking I identified the failed drive as being one that was originally supplied with the MD600 in 2013. It was a Seagate 'Desktop HDD' 2TB ST2000DM001. I suppose 7 years isn't too bad particularly as the other drive failed in 2016.

I'm slightly surprised that the system would not work (no MD600 in Configure; no Control:PC) with one drive being faulty and one functional. Or is this perhaps a way to make sure one is aware there is a faulty drive? It does work with just one drive in one of the slots.

Interestingly, having put two good drives into the MD600, the orange LED on the ethernet port at the rear is illuminated (flickering) but there is no green LED. On the MS600 there is a green LED (flickering) as well as an orange one.

I'm still puzzled as to why temporarily unplugging the ethernet cable from the MS600 should clobber a hard drive in the MD600. J.

Control:PC, MS600 & MD600, Audio Note M5 pre-amp, Conquest power amps, Magnum Dynalab MD108 tuner, Duevel Bella Luna speakers. Approx 2000 albums on Sooloos - wide range of genres.