Since I’m not an expert in this area, I’ve got only one question, which may or may not be useful. 
 

The path indicates the name ‘dropbox’ in it. Is this data you’re attempting to access stored on your computer itself, or in the Dropbox ‘cloud’?

It is a folder on the computer itself.   

It used to work before, so I don’t think that can be the problem. 

Hi @HeatherChloe,

For Music Library errors, and specifically access denied errors, it would be best to reach out to our support team. They have the tools necessary to troubleshoot and resolve the issue with you.

I hope this helps!

Getting this after the updated Sonos app.  Companies that update software that destroys a working system should pay US money.  This was the last straw, I just clicked “uninstall” and will sell all my gear.  Cannot even express how angry I am - I had a system that just worked and in seconds Sonos destroyed it.

My system just did an automatic update and now everything is gone. When I try to add the music folder I just get a 913 error message. What is happening? I need the system today, I have spent hours making a playlist this week for a family party today.

I installed the update a couple of days ago and lost all of my playlists.  I can no longer “Add” my playlists back using Mnnage/User Library Settings/Add, as I have always done with success since I first statrted using the SONOS App.  When I try to add back my music and playlists, I get an error message “Sonos was unable to add the music folder.  Reason: Unable to add the shared folder...”.  So frustrating!!!  I have tried multiple solutions, as suggested onlne, without sucess.  So myu Sonos system is simply used as TV spekers now…..

So Sonos took away our ability to play local files from our phones (at least on android) a while ago, and now they have deleted my local library from a mac mini I use as a home media server, and I can no longer add it back to the app, as it says it is unable to add the music folder, despite file sharing and full disk access being on.

Would Sonos like to buy the 11 speakers and 2 amps back from me since you’re taking away my main method of listening to music.

Also, this new app is a complete joke.

EXACTLY the same here, did the “update” and now can no longer add Music Library to the system … ERROR 913 ….. this is ridiculous !!

Same issue here: Everything worked fine on my PC until I updated the PC app. Is there a way to install an older app? I seem to have 16.2 now. Even with updating the app I see a fake error message (“something went wrong with the update” or so. Can this joke of a company get anything right?

Having mp3 files stored on my PC was my main method to play music through my SONOS Move 2 speakers. This is now completely gone. I don’t care for the multitude of SONOS radio channels that suddenly appeared. These do not contain the music that I collected over decades and that I had paid for. 

I got on a chat with SONOS support and after 15 minutes waiting was able to reach a support person. He claimed that the issue is with SONOS now requiring SMBv2 or SMBv3, and that SMBv1 and http are no longer supported for folder access. He had me try to change a setting in Windows Control Panel. The checkboxes he said to uncheck (by SMB 1.0/CIFS) in ‘Applications’ already were unchecked by default. No resolution here…

I confirmed later that Windows 10 and 11 systems have long abandoned SMBv1 anyway, so this whole story was a red herring. 

I was advised to call phone support. I am seeing 60 minutes to 90 minutes wait times...

wow… really it’s this BAD

I have the same issue.  Cannot add music library.  No use trying “support” as you have to wait for over an hour.  What say you sonos? Your reputation is on the line.  Do you care? Are you trying to get extra money by suggesting a whole lot of paid services? Do something about it, or at least respond to all of the people complaining, otherwise it is at your peril

I’m also finding the local music library to be completely broken after the recent update. I’ve worked around the issue by spinning up a plex server in a virtualized container and mapping my local music as a library in plex.

Holy crap, Sonos!  What did you do?  My sonos is broke!  Same error as everyone else!

Sonos was unable to add the music folder 913

was working fine and now lost all connections.

This is crap - all my music that I’ve spent years collecting on my NAS is now unavailable - WTF is Sonos up to ?

PROBLEM FIX:  Here’s are the steps to fix the problem:

Sorry, nothing works, not even the access to MyMusic on my own C: drive. 

I have exactly the same issue after the recent controller update. Finally got through to Sonos service support, and after about 45 mins (with them even taking remote control) they could not fix the problem. So now cannot stream from my Mac to my Sonos products. Really frustrated! Has anyone found the solution?

Is really true that Sonos only allows MAC OS hard drives to be added? This seems a terrible limitation and a reason review warnings that Sonos is not a good choice as most computers and systems are not OS.