I sympathise . I too have had constant problems and playback issues and am wondering if it’s possible to sell on a Lifetime Subscription ? Vanishing Nucleus + (A) Library
Perhaps , Amarra or JRiver or even Vlc or Foobar , although not on a par with Roon usually , will at least give me the gift of music for Christmas 
If you search the forums you will find many other pleas for help from @support so I guess they must be a bit swamped but it would be nice to get an acknowledgement and tip that help is coming hopefully before Christmas . Before bedtime last night my Roon Nucleus+ library stood at over 45k tracks but this morning
its zero !
Best of luck in finding a fix
M
