Sorry, but I have to ask this because it has been known before… have you accidentally muted to speaker?

What sample rate does the file have?

No the speaker is not muted. 
Sample rate is 44100Hz.

Then it should play fine.  What software did you use to rip it?

How are you playing it? As part of your Sonos Music Library?

I seem to recall there is some software on the PC that rips but occasionally produces silent tracks in Sonos, just cannot recall the name.

Try another ripper.

The software is NCH Express rip. Works fine when I rip as mp3.

The track I ripped shows up on my Sonos music library and is playing, but here is no sound.

It’s not the end of the world if it doesn’t work but I keep reading that FLAC is better quality.

You absolutely want to rip in FLAC quality, never MP3. 

There is a free program called EAC, exact audio copy and really should be the first application to try.

Given that this file “should” play, I think trying another ripper is a sensible next step, and EAC is a good option.  It won’t take long and will either solve the problem or narrow down the possible causes.

This may be of interest:

https://nch.invisionzone.com/topic/37180-flac-files-issues/

Sent a message to NCH to see what they have to say.

Thanks though to all of you for your replies.

Okay folks. Downloaded EAC this morning and it works! 

Good news.  Thanks for posting back.

This is what I sent

> I have ripped a cd to my NAS as a FLAC 16 bit file to then play on my Sonos system.

> When I select it to play it plays but there is no sound.

> According to the Sonos community site there was a problem, is this still the case please?

This was the reply

Hi,

Sonos currently support only mono and stereo FLAC encodings, with the first channel being the left, and the second channel being the right.

can you check how many channels it has

Regards,

Jose

NCH Customer Service Team