Same thing - all of my music library from my iMacx that was accessible on Sonos yesterday is gone. I have no idea what the heck happened or how to fix it. The “upgrade” to the Sonos app is a complete clusterfuck.

Sorry: you may find “wait a month” to be the solution. 
 

Same here.  Had to reload entire library with new path just for this ‘improved’ app to find my library.  It’s all there but for the playlists, which simply say “no selections available.”

Larks Tongue, could you tell me how you reloaded the new path? What i’ve seen when trying to do so are grayed out options… I’m sure many would appreciate a step by step guide, especially if you have a Mac!

Packet, I’m on a windows 10 machine.  Sonos rep had tried different protocols, and even wanted to change admin to an email address.  It was getting a bit to funky for me here, so I told him I would fiddle with it from here.  I simply followed Sonos directions for linking to the library.  It automatically renamed the path for me.  I am no tech guru, so further explanation is beyond me.  FYI the previous path name chosen by Sonos was my PC model #,  which did not remotely reflect the actual name of the music folder.  This time Sonos named the path the same as actual file name.  

Thanks Larks Tongue for the reply. I’ll keep fiddling with it until Sonos puts things back where they used to be!