Remember, Sonos uses SMB to ‘find’ the files, so you need to go in to the settings for your NAS and ensure SMB v1 (which is all S1 can use) is turned on. Windows is more forgiving.
 

 It’s not uncommon, at least in my experience, for updates to the NAS’ operating system, for the manufacturer to turn off SMB v1 in an attempt to ‘help’ you. I suspect if you turn it back on, you’ll be fine. 

Thank you Airgetlam as I think this has at least approached the source of the problem. Before seeing your message I had deleted the library address and tried to add it back in. Can’t do that and getting an error 900. Followed the regedit instructions for changing the stack size but this didn’t help. Anyway, on seeing your note I got in to the Synology NAS and finally found how to switch from SMB2 to SMB1. The trouble is that that has now knocked out my ability to access any of my Z folders from file explorer - eg add or delete music files or photos or backups - can’t even see the drive there and it won’t let me “map” it. As if that weren’t enough the problem is still there on the Sonos controller - indeed I’m further back as I can’t even select music files or folders or directories. 

So I think I’m looking for. How from being in SMB1 can I manage to get Sonos to find the directory, and if I succeed in that is there then a way of being able to use file explorer to access the NAS files? If these things are mutually exclusive on windows 11 and I switch back to SMB2 is there any other way of getting the music access back on Sonos?

Update (hold replies for a while)

It’s late anyway but next thing I’ve done may take a couple of hours of update.

I went back to Synology and managed to find a way of making the settings for minimum of SMB1 but maximum of SMb3.This immediately solved the FileExplorer problem. It also then at least allowed me within the “add music directory” programme in Sonos to find the network and point to the right place. And better still, it’s now saying that it’s updating the music library. From memory from years ago this could take a few hours as there’s hundreds of Gigabytes of music files. When this is done I still don’t know if I’ll just be back to where I was - selecting folders and albums and tracks but will they be able to play or will the error message come up again. I will update….

Later versions of Windows disable SMB1 by default. (You can re-enable it, but it's not recommended.)

Sonos S1, however, can only use SMB1. 

In short, you need to enable both SMB1 and SMB2 (at least) at the NAS, which is what you have now done. You should be fine. 

Your earlier experience, of being able to search and enqueue tracks but not play them, was because Sonos held the index in the players but was unable to fetch the actual files for playback. 

Thank you, Bruce and “ratty”. Fantastic! It is now all working both from the desktop and the phone! What a shame the Sonos helpline people didn’t have a clue.

Brilliant. Thank you so much for bothering to help on what probably sounded to you like something obvious.

Oh dear. Unfortunately library playback is something of a minority interest these days.

In fairness to them, however, the problem wasn’t triggered by the new Windows 11 laptop (per this thread’s title) but with a background change on the NAS.

@Denisparkesathome 

“I went back to Synology and managed to find a way of making the settings for minimum of SMB1 but maximum of SMb3.This immediately solved the FileExplorer problem. It also then at least allowed me within the “add music directory” programme in Sonos to find the network and point to the right place.”

How did you do this in Synology? I have the same issue with a Synology NAS and they said they couldn’t help, thanks

Graham