I use m3u playlists created elsewhere to play my SMB shared music on Sonos.

The playlists are imported/added through folder add in library.

All files are on the same share, in the same folder structure.

The playlists are added properly as far as I can see in the (Windows) desktop app and it plays fine when I hit shuffle until it stops randomly. 

I can see (on screen and in the useless help/log) that Sonos desktop app thinks the share does not exist (or the file, the wording points to the whole share) "Unable to play XX - the share //XX does not exist".

It was playing just fine until this. So I hit play manually on the songs it thinks it cannot access and sometimes they play right away, sometimes Sonos keeps stating the same error for a few tries and then plays it anyway. I’ve also seen it playing a file while simultaneously saying that it cannot play it because the share does not exist.

What is this? Is there any better logs than the help/error log that says almost nothing?

Just to weed out some possibilities; it’s obviously not the playlist format (cause it’s read, added and plays just fine apart from some songs), not the path/share (see aforementioned), not the file format (cause the file sometimes plays fine). However, it is as far as I can tell almost always the same few files that Sonos seems to be unable to play - again though, it plays them just fine sometimes and when I manually insist.

I’m kind of irritated.