Hey Guys:
Occasionally (about once a week) I'll open a previous project in Sonar.  When I hit "play" there is no sound.  Then, if I close the project and immediately reopen it, it plays fine.  Any thoughts on what's happening?
 
Thanks.

do you use a control surface ?
its possible your hardware fader is pegged off.
 
more info will help here. like for example..
when you have no sound, do you see meters moving ?
 
tried headphones when this happens ?

- What audio interface and driver mode, ASIO or...?
- Do you use ASIO4ALL?
- Do you have your audio interface set as the default playback device in Windows or do you reserve it for SONAR and other dedicated audio apps?
- Do these projects have any recorded/imported/frozen audio in them or are they all 'live' soft synths?
 
If the audio meters are moving (good question, Chuck), and you don't hear anything, I would guess that the driver didn't respond to SONAR's request to open the audio ports, but it's hard to say why - possibly some 3rd-party program not giving up control.
 
Next time, try just toggling the audio engine off/on by the button in the Transport module.

Chucke and BF:
Thanks for the responses!! To answer your questions:
 
I do, in fact, see the meters moving, but don't hear any sound. 
I don't use a controller surface.
Headphones don't have sound either.
 
No Asio4all.  I use the drivers for a Roland Quad capture interface.
I do have my interface set as the default playback device for windows.
The projects are of all sorts.  Sometimes only midi.  Sometimes only audio.  Sometimes a combination.
 
I'll definitely try toggling the audio engine, that seems like an easy fix.
 
Again, thanks for your replies.

Hey Again,
 
It's happening every few minutes now!!  Yikes!!  Iv'e toggled audio off/on, but that doesn't fix it.
 
Could I possibly be hitting some type of keyboard command without realizing it?

Does solo come on for any muted track?

Sometimes I have to twist the output fader on my UCX interface to start it moving signal after a power recycle.

In general though, I don't have this problem.

I've had this happen when I pull a USB drive between sessions. It's as if Windows forgets where everything else is supposed to be wired to. Meters work, but no sound. After another reboot, sound returns. However, I have not seen it reoccur intermittently. That sounds like something different...
 
Regards,
Dan

Make sure you have the latest QuadCapture driver, and to Dan's point about USB, don't let Power Management turn off USB ports and don't let your PC sleep/hibernate if this is occuring after that.
 
Also, try ensuring that 'Always Stream Audio Through Effects' is enabled in preferences, and maybe add an empty, muted audio track with Input Echo enabled. When I've had issues like this with certain interfaces/drivers in the past, having input monitoring enabled helped keep the audio engine and ports alive when the transport was stopped.

It funny, as time goes on we get to know our own systems well and realize what is causing problems.
with me, it took a while but I have a Mackie MCU unit. and I choose to not use the motorized faders unless im doing mixing or automation.
well a few times I have bumped my Mains fader. with it not being used (in the 0 dB state)
once it is bumped, it thinks you are trying to change levels. thus my Hardware output goes to 0dB / no sound at all.
 
that's why I mentioned that. sometimes its the little things right in front of our face that we over look.
maybe not in your case :-)
but those are sometimes the things worth checking, IE- The obvious.
 
I wish I could give you more advise but you have a few guys here, who in my opinion are the best at trouble shooting.

I've been having a similar problem. For me, it's not when I first open the project, but at seemingly random times while I'm working.
 
Sometimes, the playback would continue fine, but suddenly there would be no input. As with jude77, if I close the project and reopen it, I'm back in business. I always disable the wireless network adapter before starting, because of audio problems in the past. One time I noticed that the Realtek adapter, which had been disabled, was back on, probably from a Windows 10 update. Since I disabled it again I haven't experienced that. I have no idea whether or not that is what actually made the difference.
 
However, recently on one project, which is all MIDI so far, it's the playback that will stop functioning. I don't recall it stopping while playing, but sometimes after I've stopped it and started again. This time, the meters show activity for playback and input as well, just no sound. Again, closing and reopening returns things to normal. I've been spending time with two other projects lately, and haven't been experiencing this with either of them.
 
I've been assuming it has something to do with my soundcard. It's an M-Audio Audiophile 2496. It has no Windows 10 driver. I'm using the most recent driver. However, I only seem to have problems with Sonar. Everything else (SoundForge, internet, etc.) works fine.