Unfortunately, I think the answer is “be patient till mid June”.
After much faffing around and reading numerous router and media player forums, they have all come to the conclusion I need to re-enable SMBv1 on my Sonos system, to get it back working as is has been for the last couple of years and was working fine.
So how to I do that, can’t see any settings in the Android app (both old and new) nor in the Windows app ?
My Windows PC can see the files on my router USB stick and media player fine, it’s just Sonos can’t.
Was previously really impressed with Sonos, great sound, easy to use app and played music from media player and USB stick in router 100%, no skips, no stutters, just worked. Search of my media often bought up interesting tracks that I didn’t know I had, loved it. Not impressed now, and would immediately return them to John Lewis, as not fit for purpose, if they weren’t so old. They were bought to play my music collection.
If you've updated the firmware in the last week or so, then you can't reactivate SMBv1. You have to update the source (eg. NAS, PC) to smbv2/3. Otherwise you have to buy a new source device.
Only Sonos could re-instate SMBv1 - on current behaviour, pigs might fly.
and can no longer find any of my music & my playlists, so had to work at home in silence. My laptop & phone played fine, finding all MP3 files, but laptop/phone speaker quality is not great.