I managed to get my music library back, without playlists, in July.  In late August Sonos updated and now I can’t get my music library back.  Even the Sonos Tech said I “did everything right” by following your posted procedure, and he tried multiple times - added the library successfully, but could not get Sonos to find any song in the library.

Library is connected

Path is correct.

Filer persons for Share are correct.

BUT Sonos just shows “No selections are available” 

I don’t even know what that means.

Interestingly, Sono’s plays music from my library on based on the ques I manually made and saved as “sonos favorites” in the Sonos System.  I don’t know what is going on.