I have not done any recording since early in 2017 and in the meantime (without thinking much about it) I got the Win 10 Creators update (v1703). Today when I try to play any project in SONAR (Platinum, v22.11.0 BUILD 111 [2016.11]), I get a popup "unable to open audio playback device." Device is Focusrite Scarlett 2i2 (1st gen.) USB 2.0 audio with latest Win driver and it works fine in other audio tests (Win Media, iTunes, Band-in-a-Box). My SONAR support membership ended 3/1/2017 (not intentional, missed the boat somehow, busy with non-musical life). 
 
I've tried rebooting, changing driver models in audio settings, updating device driver (Windows wouldn't let me as it had latest), disabling the PC's onboard audio driver. I searched KB and forum which made me suspect Creator update but aside for disabling onboard audio, I couldn't find anything relevant. Any suggestions? I'm not sure how to re-up support subscription or updates at this point but I will if I need new build to get around this. Since my subscription ran through Feb. 2017 and my version is 2016.11, maybe there's a more recent SONAR update I haven't installed yet (I will check). But Win Creator update was since March (I think). UPDATE: I installed 2017.01 (latest version available to me) and behavior is the same. 
 
Thanks,
Bruce
 
My system is CybertronPC with AMD FX-8300 8-core processor, 3.3 GHz, 16 GB RAM, running 64-bit Windows 10 Home (Creator Ed., v1703). Latest updates on Win10 (automatic). Latest Win driver for Focusrite Scarlett 2i2 (first gen).  

I had the same problem with my Focusrite 6i6 1st gen after my desktop updated to the latest Win 10 update. Band in a Box, iTunes, Reason and Sonar Platinum had no sound at all. I tried to install the driver again through control panel to no avail. In the end I resorted to uninstalling the driver and the scarlett interface through add/ remove programs. I then unplugged the interface and installed the driver again. Once done the menu said to plugin the interface back in .Everything is now back to normal. My laptop has not installed the very latest Win10 driver and I have had no problem with it at all. I do hope this helps you.
Cheers from Oz

Also check Windows sound card settings. Certain updates have a habit of resetting defaults on you. Those settings will affect all other programs running within Windows.

Thanks so much for the tips! I should have thought to try a full uninstall of the Focusrite drivers. When I reinstalled, other audio programs worked (as they had before), but SONAR had the same problem as before. As an additional test, I happened to try launching the standalone application of EZdrummer-64. This too failed (no sound, can't access device) but it gave me an audio settings dialog with a "Reset Device" button. I clicked that and the dialog displayed some latency numbers and EZdrummer could make drum sounds. Better yet, when I launched SONAR, it too was now able to find the Focusrite audio driver and produce sound normally. There was probably a way within Windows or SONAR that I could have done that reset but I couldn't find it. 
Thanks again!
Bruce

I have four Focusrite Scarletts, various models 1st and 2nd, and I have never seen this button.  Thanks for the tip.