All faders pulled down - can still hear audio tracks

[deflint]

I am starting to mix a new project and started by bringing all the faders fully down. 
No tracks are solo'd or muted.  The Master Bus where al the tracks are currently routed is set to zero.
Why am I able to still hear all the audio tracks?

Edited June 13, 2021 by deflint

[Glenn Stanton]

maybe you have some pre-fader connections enabled to the HW IO? e.g. a send which is sent to the HW output which is pre-fader would likely send that content to the HW output (which is on the buss side of the console and may be hidden - so grab the far-righthand vertical divider on console and pull it to open the HW (and also check in track inspector for any pre-fader sends or outputs - extreme routing flexibility is a double edged sword sometimes... ? )

[deflint]

Thanks for taking the time to respond. I don't see anything on the HW pane or Track settings that would explain this.
As a test I started a new project, recorded a couple of measures and tested. No audio as expected so I'm thinking the other project may be corrupt somehow.
I'll export the tracks to a new project.
Thanks again.

[John Vere]

Open Console view.

Drag your audio interfaces strips from the right hand side. 

Now mute the master bus. 

Observe the Audio interface meters. if they are still showing a signal then a track is outputting directly to them.

Check the output settings of any sub busses. They should all be going to your master buss including any effects busses. 

Check there are no axillary sends routed directly to the interface. 

There's no need to rebuild this, projects do get corrupted but the signal path cannot be corrupted.  
 

One other item is it looks like you’re using on board audio. Make sure you use WASAPI mode and not ASIO 

Edited June 14, 2021 by John Vere