I finally solved the issues I was having with Sonar and they were many,(dropouts, no audio device detected, sample rates not switching from one project to another). I finally rolled back to Windows 7 and it's smooth sailing for me again. I am posting this in case it might help someone else. I see where people are having a great experience with the preview build for Windows 10 (I think it is Build 10547)but Build 10240 caused nothing but headaches for me. It just didn't seem to want to cooperate with Sonar. Just an observation...

Definitely something to do with your audio interface device drivers in the windows 10 scenario. In most cases we have observed removal/reboot/reinstall (latest) clears it, as well as doing a firmware update. A chipset and motherboard BIOS update can also help...

Otherwise it's some other issue like wrong device driver settings, or some other driver conflicting. Or perhaps windows update or some other task running at the wrong time...

The preview builds all had various nit-picky issues. The release build is running great for me. But audio system performance is largely dependent on the drivers. My Presonus drivers seem OK.

Yep Doktor, I have done all the things you mention above more than once to no avail. It really seems like Windows wasn't wanting to give Sonar control of my interface. I spent time on the phone and internet with Focusrite and Cakewalk and it always came down to something in Windows 10. I will wait for the public build to catch up with the preview build and may try it again.

Delete.

And another thing is ,Windows by their own admission says they have problems in their handling of audio which they addressed in the preview build.

Well you got my tip about routing all windows sounds to the internal sound card, then routing the output back into your interface via a lead. This issue is a limitation across all windows versions (by design). ..

Yes sir and I thank you and I tried it but it didn't make a difference in how Sonar was working unfortunately.
 

Are you running any other DAWs? Or anything that could include it's own ASIO driver ? (Jriver, cubase, Asio4All comes to mind).

No , I do have the free version of Studio One and I tried it and had no issues , but I never use it.