I presume the Core is registered with M?

Sometimes rebooting the system and waiting a few hours works with an update. Failing that a word with a friendly dealer and supplying them with your Core’s MAC address should solve it.

Sooloos, Roon, G series (with LPS upgrade), 800 series (with LPS upgrade), HD621, AC200, Prime and PS, DSPs old and new.

Purdeys, Moke, Leica, 'Blad. Only the best.