I've been experiencing project files becoming corrupted, and it's gettin me down! The interface will start acting strangely. Tracks getting out of sync, S and M buttons not functioning correctly, auto saves taking a LONG time to complete and other oddities. By the time I notice the wonky behavior, it's too late, the file is corrupted. If I close the project and restart Sonar, it crashes when I try to reopen it. Backup copies also corrupt. I've lost 2 projects to this now, One of which I had been working on for weeks. I'm going to try a fresh reinstall and see if that helps. Any other advice would be greatly appreciated.
 
I'm running Platinum 2016.10 on Win 10 64. I also run East West's Play 5 engine if that matters.

WHat interface are you using. DO you have the latest W10 ASIO drivers for it?
Is the internet on while you are working? 
Run Latency Monitor and see if background processes are using CPU. 

I got an i7 processor that doesn't break a sweat. But I am using ASIO4all right now until I can get my hands on a focusrite.  I didn't even think of the interface. Guess I should have! Thanks for the tip.

 
It doesn't matter how fast your computer is, background processes can interrupt Sonar when running a larger project. 
When trouble shooting it's always a good idea to eliminate anything that is known to cause issues. 
 
Sonar does run the best when using ASIO drivers so an interface is more or less critical to smooth sailing. 
I use the WASAPI driver on this here laptop and never have issues.however, I'm only working with midi on this machine.  
 
 

Update at least to Platinum 2016.12 to get the WASAPI compatibility updates for Windows 10.  I noticed that you are still running 2016.10.
 
Platinum had added improved WASAPI support in 2016.11, and added some bug fixes for it in 2016.12.
http://www.cakewalk.com/Products/SONAR/Whats-New#start
 
I have tested WASAPI on Win 10 and I get very good real-time audio performance in Sonar using that.  Almost as good as the ASIO driver for my interface.

fwiw, it sounds more like a play vst issue (there have been many reported) than an asio4all issue to me? that is, a plugin rather than driver issue... still, neither should result in a corrupted project? please consider sending a "corrupted" project file to cakewalk for analysis
 
and so just for kicks:
 

Platinum had added improved WASAPI support in 2016.11, and added some bug fixes for it in 2016.12.
http://www.cakewalk.com/Products/SONAR/Whats-New#start

 
does this quote (if it's implemented, how can it be "improved"? surely that's just "finishing implementation"? wasapi bugs not fixed until .12) negate all the previous "wasapi rules!!""posts? how could wasapi be so fantastic if it wasn't completely implemented and had bugs?
 
(disclaimer - i like and have used asio4all for many years without issue, but there's a default attitude of "asio4all sucks" from some of the regulars on this forum, even when they've never used it themselves, though i'm sure it's just a misunderstanding )
 
good luck!

I agree that software issues causing corruption and crashes are probably plugin related, but it's never a bad idea to make sure your audio drivers are stable as well.  One less variable to troubleshoot.
 
I have used both ASIO4ALL and WASAPI on Windows 10 and Platinum without any issues.
 
If I was going to choose one for Sonar compatibility reasons now, I would opt for WASAPI only because Cakewalk is testing Sonar for compatibility with it. 
 
However, if you plan to use any of the Cakewalk synths in standalone mode, they still only seem to work with ASIO ...

And I too have tried asio4all, was 10 years ago and XP and have personally nothing against it if it's your only option. Back then I was struggling with a Creative Audigy Card. Asio4all didn't solve my issues. Mostly  it's the 100's of posts where other people are having issues with drivers and forum members see the words asio4all and freak out.  It is known to interfere with real ASIO drivers and it's invasive to your system and apparently hard to get rid of. There lies the bad reputation. It is also worth a mention for those who may not be aware that asio4all is a WDM wrapper and is not a ASIO driver. It's name fools people. 
 
 But now with WASAPI built right in there's no longer any reason to install asio4all  and risk those issues. WASAPI would seem to be a better choice at this point in time.  
WASAPI like any none ASIO driver is far from perfect and still not a great idea if you plan on overdubbing audio. You better check your offset or your tracks will be out of sync. As I said I'm working with pure midi so it's fine for that.
 
I just might re do this test and try ASIO4all out of curiosity. It will be on a computer I don't use as a DAW for sure. You can clearly see the winner here is ASIO. 
 

Best start would be to open the file in safe mode (shift-double click the cwp in Windows explorer), then disable suspects till you find offenders. It is unclear what "corrupted" entails.

The choice of audio drivers will affect performance, but not corrupt a cwp.

This started happening to me when my VS-700 Rack Interface started crapping out on me. I've not had an issue since I dumped it for a new one. My guess would be it has to do with whatever you're using for sound.