[As usual - spoke too soon. Still not solved.] What do I do when my project is hosed?

What happens when you hit Ctrl+S, exit Sonar, then reopen the project? Is your work gone?

Try increasing the latency. But also, are you using VX-64 processors?

mudgel
Are you getting a dropout and the audio engine is turned off? If that the case you can turn the audio engine on again without closing Sonar. You may need to adjust your audio buffers to prevent the dropouts.

Clicking on the audio "engine" icon doesn't fix the problem. I just get loud clicks each time I do that. It's not a matter of dropouts. No sound, period.

I think it's caused when I use a certain VSTi. I'll just avoid that VSTi for now and hope the problem goes away with future releases. 

This definitely sounds like a rogue plugin.
 
I agree with Kalle, which plugs are you using?

mleghorn
I think it's caused when I use a certain VSTi. I'll just avoid that VSTi for now and hope the problem goes away with future releases. 

You should submit a problem report. Maybe the bakers can see what is wrong with the VSTi and either change SONAR behavior or contact the vendor and get them to fix the problem. Over the years I have seen both scenarios occur.

I doesn't seem to matter which VSTi's I use in my instrument tracks. It seems to happen whenever I have more than 30 instrument tracks. Is there an unofficial limit, beyond which X3 becomes unstable?
 
Plugins: Dune 2, Bazille, Synthmaster, Valhalla Room (reverb)
Sonar X3 Studio (latest version)
 
System info:
Alesis pentium i7
12 GB RAM
Windows 8.1
ASIO4ALL, using optical out from soundcard

Do you have an audio interface, or are you using the on board sound card?  What other hardware (keyboard?) are you using.
 
Using onboard sound puts all the A/D conversions directly on the CPU as opposed to a dedicated audio interface which has its own A/D processing power.
 
My understanding is that Vahalla reverb is resource intensive, so you may be pushing the processing limits if you are using multiple instances of it.  If that's the case, you could try routing the tracks that need it to a bus.
 
You can also freeze some of you synths to take some of the processing load off of your system.  If you need to work on them you can unfreeze (thaw?) them make changes and then freeze them again.

ASIO4ALL, using optical out from soundcard
 
Problem solved once again. 
Please purchase a proper audio interface if you wish to have a functioning DAW system. 
It is rare that you will have good results using on board audio and asio4all. Sonar is very particular about this. 
 
 

I upgraded to the newest version of asio4all, and everything seems to be working fine. I don't require much from an audio interface except stability, good sound, and low latency. I don't need any of that other stuff or anything with "fire" in the name (whatever that is). I prefer to keep everything in the digital domain as much as possible. The DAC phase happens in my headphone amp (pictured in my avatar). The headphone amp, btw, is the Burson Audio Conductor, oh, and the headphones are HD800s, and the headphone cable is the Cardas Clear. Any questions? :-)
 
The jury is still out on my current fix. I'll keep pounding on it to see if anything breaks. Stay tuned :-)

The problem with ASIO4ALL isn't necessarily with how it works, but how it affects other drivers on your computer.

Well I guess even asio4all progresses with time and my information on it is outdated. Glad it's working for you. 
You got me wondering if my old Creative Audigy with digital out would possibly work again. I certainly didn't in the past. 
Which OS are you running per chance? 

While it may be working for you at the moment - once you get into more complex projects and put more demand on conversion and effects and all that, you may one day find your CPU not able to give you adequate performance.
 
I would urge you to have a plan B, for picking up some sort of dedicated audio interface at that point (my vote is for sooner actually), which will REALLY make a big difference on how hard you can push things in your projects without having audio glitches and dropouts and crackles and dog-punting desires.
 
A dedicated audio interface will take over the responsibility for doing the analog/digital conversions and all that, which will make your CPU work WAY less hard, freeing it up for other useful pleasantries.
 
Glad you are working, though, just planting seeds in your brain with the above, for some future picking up of some sort of dedicated interface.
 
Bob Bone
 

Thanks everyone for you ideas. I'll stick with ASIO4ALL - 4 - now :-) 
 
My computer isn't doing any A/D conversion. I have one analog device that I use occasionally (Microbrute). For that I use a Tascam interface to do the A/D. Other than that, I only use VSTs. As for D/A conversion, I hope my computer isn't doing any of that either, since I'm using the optical out of my sound card to my Headphone Amp/DAC.
 
The Tascam interface doesn't have a digital out, so I don't use it as an output device. 

mleghorn
Thanks everyone for you ideas. I'll stick with ASIO4ALL - 4 - now :-) 
 
My computer isn't doing any A/D conversion. I have one analog device that I use occasionally (Microbrute). For that I use a Tascam interface to do the A/D. Other than that, I only use VSTs. As for D/A conversion, I hope my computer isn't doing any of that either, since I'm using the optical out of my sound card to my Headphone Amp/DAC.
 
The Tascam interface doesn't have a digital out, so I don't use it as an output device. 

ALL audio stored on a computer is in digital format, and when you play back an audio file, whatever program is playing it back converts that digital format into analog signal that then gets routed to the speakers.  In the same way, when you record, the software you are using to record converts the analog signal (vocals through mic, guitar plugged in, some instrument plugged in), into a digital stream that is then saved on the hard drive.
 
so, analog/digital and digital/analog conversion happens all the time when working with recording software.
 
The thing is that if you are using something like ASIO4ALL to simulate the ASIO drivers of an actual audio interface, all of that conversion (both directions), is handled by your computer's CPU.  This isn't an issue for playing back an audio file such as an MP3, but when you get into multiple tracks in Sonar, with effects and soft synths and all that, this becomes too much for the CPU to handle very quickly, and THIS is when you start getting dropouts and crackles and pops and noise.  
 
So, now days, dedicated audio interfaces exist, and the drivers for these route the files to dedicated circuitry in the audio interface, that performs all of that processing-intensive conversion to and from analog and digital, and it frees up the computer's CPU for doing other things, and having such an audio interface should eliminate problems with dropouts and crackles and pops and such.
 
So that is what I meant by analog/digital conversion (actually both directions).  That is all happening for you behind the scenes, but it is indeed taking place on your computer when you work with Sonar.
 
One of these dedicated audio interfaces can be purchased brand new, starting around $125-$150, on up to more than $500, depending on features present on the interface (number of inputs and outputs, phantom power, supported sample rates, quality of converters).  Many of the lower-end costing interfaces still have decent quality converters - they just maybe only allow 2 ins and 2 outs, versus some that allow 8 ins and outs etc.
 
Just make sure whenever you DO decide to get one, that you check to make sure they have software drivers for Windows 7 and hopefully Windows 8.
 
I hope I explained the above better this time - sorry for any confusion, 
 
Bob Bone