Problems building and updating library - Music Files Not available error during update

  • 10 April 2022
  • 3 replies

System 2 x Play 1. Sonos app on PC. Media on QNAP NAS. PC & NAS hardwired to Router.

Trying to add Music files to library. Building from scratch. Adding folders serially. Once the total number of files becomes large the addition takes a very long time until it reaches the point were the system just spins indefinitely. Had about 30000 songs added and cannot add anymore.

Eventually system seems to time out with Music Files Not Available error. ‘Source’ is no longer available … yet I know the system is live. So frustrating. Tried. I know that this is a large library but in the past just used to get the library is too large error.  



Best answer by buzz 11 April 2022, 00:28

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3 replies

A copy of the library index is stored in each player. Since storage is finite, it is possible that you’ve run out of space. This could be due to the metadata size( Track names, Artist, Album Artist, etc.). The absolute track limit is 65,000 tracks. There can also be trouble with stray characters in the metadata.

If you submit a diagnostic and check with SONOS support, they can tell you if there is a problem with excess metadata. In the desktop controller you can go to Help → Error Log… . Sometimes there is a useful message here.

Music Files Not Available error. ‘Source’ is no longer available … suggests that something in the chain is going to sleep or there is a network issue of some sort..

Userlevel 1

According to a Sonos support person the location of the music index depends on the setting chosen when adding a link to the music library. There are 3 options if done from the PC controller application:

  • My Music Folder (on local PC)
  • Another folder or a drive connected to my computer (Local PC or USB ...)
  • Networked device (ex. NAS drive)

Apparently it is always stored in the folder connected to the Sonos controller. But then when I connected to my NAS in that folder I cannot see any directory (even a hidden one) which contains this data.

Does anyone know where the location of the index is?

If it were in each player than it would need to replicate the up to 65,000 index data over all devices in the Sonos network which is a lot of traffic and frankly a very bad file and redundant file storage solution. 



A copy of the library index is stored in each player and is not visible to other applications. Yes, there is a bit of network traffic while the index is being updated, but modern networks are rather fast. The advantage of this scheme is very fast access to the music files.  The music file is available very rapidly because there are minimal transactions (over the network) with the external file system.

In fact the control application can be shut down or even removed while music tracks are playing and the music will continue.