Many years ago I worked at a place where we all had external drives plugged into cinema displays that acted as Time Machine drives for our laptops. The backups

Many years ago I worked at a place where we all had external drives plugged into cinema displays that acted as Time Machine drives for our laptops. The backups regularly failed, OSX would suddenly decide it didn't like it and you'd have to clear it and start again. I don't believe Time Machine could reliably cope with drives that were periodically disconnected perhaps. I had the same problem with a NAS device and my personal mac, it would periodically just decide the backups were screwed.