You have to share the drive, then from the Sonos app, delete the old index and add the new location.

The drive is shared; that’s how it is registered on the network.  I didn’t have any problems with this exact drive for almost a year, and only now is it a problem.  Additionally, the old location is automatically gone from the Sonos app, since it can’t update the index (scheduled daily at 2 AM).

Moving the drive to your PC is going to change the network address.  You need to delete the old index and add the new.

When you say ‘delete the old index’, I assume that means the Remove button in the Sonos app.  If yes, the index is no longer there in the app, so is there a way to ‘force’ remove it from the devices (assuming that’s where the index ‘lives’)?

Yesterday’s update of the software did not work either.  Is it possible that my new router (Eero 6+) is at the root of the problem?

Using a SONOS controller, you need to remove the old library index and install a new library using the current library location. SONOS does not write to or remove any files. As the name implies, SONOS is simply building an index of file locations. A copy of this index is stored in each player. When you select a track to play, the controller simply sends the file location to the player(s). Once track play starts, the controller can be shut down or uninstalled. Play will continue until the player(s) run out of instructions.

Experiencing issues with your music library index on a Network-Attached Storage (NAS) can be frustrating, but it's a common problem that can have various causes. Here are some possible reasons and solutions to address the indexing failure:

1. Network Connectivity Issues: Check the network connection between your device (computer, smartphone, etc.) and the NAS. Ensure that both devices are on the same network and that there are no connectivity problems like dropped connections or slow speeds. Unstable network connections can interfere with indexing processes.

2. File Permissions: Ensure that the user account accessing the NAS has the necessary permissions to read and index the music files on the NAS. Improper file permissions might prevent the indexing process from completing successfully.

3. Media Server Configuration: If you're using a media server (e.g., Plex, Twonky, DLNA) to index and serve your music library, review its settings. Check if the NAS is correctly added as a media source, and verify any folder settings and file format compatibility.

4. File Format Support: Confirm that the music files on your NAS are in a supported format by the media server or indexing software you're using. Some servers might have limitations on the file types they can index and serve

The “remove” index is only available if there was only already there to remove.  What has happened is that the original index is gone, and when I try to reindex, it bombs out and does not create the index at all.  Interestingly, there was a brief appearance of an index from MediaMonkey on the music sources, but that has now also disappeared.

Here’s a screenshot-note the MediaMonkey Library, but the empty library:

I’m having the same issues, and called Tech Support. They act like they don’t know this is happening but I see it’s a common occurrence.

With me, it’s a USB flash drive attached to a router with USB sharing turned on and the drive Network mapped in Windows.

Sonos allows me to add it to my Music Library but when I try to Index it a day later with new files, it always fails and says the drive is unavailable. Yet Sonos is still playing music off of it.

Please fix this Sonos. It appears to be a known issue.

I am also getting the unavailable message after it starts indexing (while still completely visible and readable/writeable through Windows Explorer).  I am not able to play anything from the designated drive.