Hello Chris, personally I would point the finger at Windows 10 breaking the sound card driver. I have a number of previously working USB sound cards broken by Windows 10.
Just to confirm that when moving tracks to play in Live Assist mode the tracks appear but do not play at all
Chris Capel
Live Assist mode does not work after a recent Windows 10 update plus a new driver to the Tascam sound card that I'm using. Desk Mode works fine. Has anyone experienced something similar?