Have you tried playing the same files on a Windows or mac music app?

Hi thanks for responding,  It works when i play it from my NAS via my mac the same file also plays fine on my Sony NW-A55 so im lost!

Hi @Matt.hutch1966 

Thanks for your post!

I recommend you rename the file’s parent folder to not include the question mark. Re-index in the Sonos app, then test. Note that any playlists that include any files from this location will need to be updated with the path change.

Question marks are used as wildcard characters in many operating systems - I’m surprised you were able to include it in the first place.

I hope this helps.

Edit: If you use software that downloads the CD info before ripping the CD, you may want to check if there’s an option to prevent illegal characters being used in filenames, or use different software that has this option/filter. 

Thanks Corry

A number of my albums have ?’s and play fine - the only solution was to delete the NAS library from Sonos app and reinstall and surprisingly everything is now fine. I think the update music library function is flawed 

Hi @Matt.hutch1966 

That’s pretty strange, but I’m glad you found a solution - thanks for sharing it here and updating us!