I was having no issues at all. so I refreshed my pc. Had to go back to win 8 then upgrade back to win 10.
I go to reinstall SONAR and.......I get a message that it doesn't support my OS, WTH? I'm pulling my hair out trying to figure this out.
 
And go!!!

What do you mean by "refresh my pc"?
 
Did you fully uninstall SONAR properly before reinstalling?
 
This shows how:
 
https://www.cakewalk.com/Support/Knowledge-Base/2007013392/SONAR-2015-Clean-Install-Instructions
 
When you do this, always run "As Administrator"

DaddyV
I was having no issues at all. so I refreshed my pc.

hmmm, not sure I understand that.

From what I gather this means a total reinstall of the operating system. 

You might want to do the following before installing Sonar

1) Make sure you have downloaded and installed all Windows updates - especially the Vdist c++ 2015 update
2) Make sure you have installed the latest version of all hardware drivers by actually going to the manufacturers web sites rather than relying on Microsoft.
3) Download and install the latest ILOK licence manager if required.
4) Download the latest Melodyne from http://www.celemony.com  (which currently is 4.0.4)
5) While you're at it , download the latest XLN installer and Addictive drums if required

Then download and install the latest build of Sonar that you're entitled to

And as mentioned , do all of the above while logged on as an administrator - including the installation of Sonar and reactivation of plugins that require it.

Yes, I did a fresh install of my operating system. Apparently though, I forgot the most important thing-RUN AS ADMINISTRATOR.......
 
It's back to working again, now I can download my plug-ins all over again.

The audience is listening....

ahhh thee ole administrator. been there, done that..
your not alone man

You are or you're; me thinks.