I did a rescan of all plug-ins and the subject plug in came up as an error   "The following plug in caused an error during load".
"The failure point was reported as MAIN CALL".
 The options are Disable Plug-in or Enable Plug-in (Risky).
 
What is this and how do I fix it?
 
 

Its fixed, I copied the Rmix folder from my Win 8 Sonar installation to my Win 7 Sonar installation (replaced the folder) and the VST scan does not report any error.

But, what is "Rmix"  Which VST is this?

http://www.cakewalk.com/Products/SONAR/whats-new.aspx under "New plug-ins and tools".
 

OK, I see what it is.  I've never used it.