https://support.sonos.com/en-us/article/share-your-macos-music-folder-with-sonos#

 Did you try this procedure?  Don’t know how old these instructions are.

Yep, same thing is happening to me after updating to latest MacOS, Sequoia 15.0.

Same issue after updating to latest MacOS, Sequoia 15.0.

Can’t connect to my system from my daughter’s (latest model) Mac since installing 15.0. My Mac is a 2019 with the Intel chip, and that still works. Has anyone with a newer Mac been able to connect?

Found a solution that worked for me on Reddit: https://www.reddit.com/r/sonos/comments/1fiz5cj/comment/lnksluh/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button. Basically, check the setting (Settings/Privacy & Security/Local Network/Sonos) and toggle Sonos on.

I had the same problem, but managed to get things working by going to Manage->Music Library Settings … and adding an additional folder, which had a few random music files in it, to the list of shared folders. After the library had been reindexed, everything could be played again, including material in the folders which had originally be shared. I was subsequently able to delete the folder I had added without breaking things.

The root cause seems to be something to do with the need to add an entry to the Access Control List of shared folders.

This is such a frustrating problem and has been going on for months. When are Sonos going to properly sort this out? You should just be able to click on sync the “My Music” folder option and it just work like it used to do rather than faffing around with the NAS option and constantly adjusting settings to get this to work. I have my music library accessible for a while then something changes/there is an update and it can no longer find it again. I am using MacBook Air M3, macOS Sequoia and the Sonos app for Mac but this issue has been going on months now and no one at Sonos is getting it fixed. I eagerly updated my app this morning hoping it would work and it’s the same old BS for me I’m afraid.