Hi all..
Once again I have run into the same problem - no audio out from my Focusrite Pro40 and it's driving me MAD!!
OK, some facts which may help:
1  Pro 40 shows up as ticked as the I/O in the input/output section of preferences.
2  Inserting any VST brings up its window correctly and I can select and play all the patches
3  Using the Wavestation VST, the keyboard on the screen follow the master keyboard input strokes
4  The Sonar midi and audio Vu metering are displaying output levels when playing the master keyboard - as is the master output in Sonar
5  Mix 1 in the Pro 40 mix control panel is set up to output Left and Right on the first two monitor outputs
6  The metering in the Pro 40 mix control panel also shows an output level when playing a VST
6  There is no audio from either the monitor outputs or the Headphone output.
7  The pro 40 is the only audio interface in use - the sound card in the PC is disabled
8  The pro 40 is correctly shown as the input / output device in the sound options of the PC
 
I am now at a loss - having tried all I know to sort this out.
 
Any bright ideas out there???
 

I've seen what you describe (incl. the meters indicating audio on both Midi and the VST without any audio) and have found two approaches:
 
1) This one makes no sense but it worked just yesterday: If I have chosen "Edit" or "Move" in the Tools Module there is no Audio. Switching back to "Smart" and the audio comes back. When audio goes away, my first attempt is to click "Move" then back to "Smart".
 
For reference, the "Tools Module" I refer to is the one in Fig 113 in this link:
http://www.cakewalk.com/D...;help=Tutorial6.3.html
 
2) save and restart the project
 
I generally edit in the PRV, and lose audio during the edits. That's probably why 1) "works", even though it makes little sense.
 
FWIW, I use a PCI Creative Labs soundcard, so it's not your interface.
 
Hope this helps!

The metering in the Pro 40 mix control panel also shows an output level when playing a VST

 
This indicates a problem downstream of Sonar, either with the Focusrite or the rest of your monitoring chain.

Is the mixcontrol set to follow the DAW? I have a Saffire Pro 40 and have no problems with the interface.