Hi @equalizer81, thank you for reaching out to the Sonos community and for letting us know about your concern. Let me help you out on this.

First, I'd like to ask some questions to isolate the issue so we can determine the path towards a resolution.

1. Any update or changes you made recently with your network?
2. Are you getting an error message when you tried to play music? What’s the error message?
3. Have you tried removing and re-adding your music library?
4. Have you tried updating your music library?
5. Have you configured your MacOS firewall to work with Sonos? 
6. Do you have an antivirus installed? You may need to check the firewall configuration settings to ensure that it's not blocking Sonos.

Please run a diagnostic from your MacBook and reply back with the confirmation number for us to check. This will allow us to see how your system is functioning, and help provide a resolution. We'll wait for your reply.

Hello. Below are the answers to your questions. I ran a diagnostic and the confirmation number is 1328741698.

1. No, I have not made changes to my network.
2. Yes, the error message is “Unable to play (song title.mp3) - the file (//file path.mp3) cannot be found.”
3. Yes, I have tried removing and re-adding my music library.
4. Yes, I have updated my music library numerous times.
5. My Firewall is turned off.
6. I do not have an antivirus installed.

Thank you.

Hi @equalizer81,

Thanks for the update and for submitting the diagnostic report. I’m sorry to hear that after performing all the steps the issue remains unresolved. Let me check it for you.

Upon checking the report, an audio playback failure due to transport errors was detected in your Sonos system. Your Sonos is unable to play selected content. This could be one of the reasons why you’re getting an error.

I appreciate your time and all your effort working on this, I would like to recommend contacting our technical support team for more in-depth troubleshooting steps. Please let us know how it goes with our technical support team. We are always here to help. 

I’ve spent enough hours of my life on the phone with Sonos technical support to know that it’s a waste of time. I’ll stick with the community forums on here and hope that one day Sonos makes a viable music player.

Hi @equalizer81, 

Thanks for your reply and for updating us. I truly understand that you don’t want to spend time reaching out to our phone support team. At this point, it’s the best option to perform real-time troubleshooting with your music library. Our phone support has the tools to check what's going on in your system and to remotely access your MacBook to check other settings and configurations. Of course, we can also wait for feedback from the community members, they might have suggestions about this. If you need help with any other information, please be sure to let us know. We are always here to help out.

I have wasted hours if not days of my life on the playlists in my iTunes/Windows/NAS/Sonos system, and have recently exported all of my 700 (!) playlists in m3u format and ditched the xml file. And when I alter a playlist, I just export the playlist to a new m3u file

I suggest that you try exporting the playlist in this way and if it works, you have a possible route out of your misery. I feel your pain ...