SOLVED! Audio output lost on one project (not others)

[EDT]

Hi all, I have been working on a project this morning and it has autosaved several copies to the project folder but, having exported the audio to create a final FLAC mix, the audio within the Cakewalk project is no longer audible. The console view VU meters are showing audio being played but no sound is reaching the speakers/headphones. I can't therefore do anything more to edit the project 

I have undone any muted tracks and checked the outputs from each track go to the Master and Master outputs to speakers.

I should note all my other projects are ok (and Ableton also works fine) it's just this one project which I have been working on for a few hours today. I haven't to my knowledge changed any of the sound settings on my laptop.

Notably the first version of this project I saved (before all the autosaves and later manual saves) plays fine but that doesn't have any of the additional tracks and work I have put in today.

Is there a way I can do something within this particular project to correct this?

EDIT: I have a second monitor attached to my laptop by HDMI cable. Routing the Master output to the HDMI makes the sound audible but then re-selecting the laptop speakers sends it inaudible again.

 

Not sure how sorry, but this seems to have something to do with the audio settings on the laptop. In Cakewalk it is still showing the Master outputting to the HDMI, but the sound is coming back through the headphones attached to the laptop....

No idea either!

I have tried this on other projects and it is fine switching between the HDMI output and the speakers output.

Is this something to do with how this particular project has autosaved perhaps?

Thank you for your assistance.

Edited April 7, 2020 by EDT
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