Azslow3,
 
To be honest at this stage I don't think there is any other option than a clean install of Windows. I am going to take this route and see how it goes. Still a bit upset as to how Cakewalk Tech Support is non existent. What's that about?
 
Anyway, thank you for all of your advice and tips on the matter, unfortunately we couldn't resolve it and I know I do not have time to sit around waiting for a response from support. As usual, paying for services we don't get to go along with our mobile phones and all the rest. The consumer always ends up out of pocket.

So... 3 weeks on and Cakewalk has still not contacted me regarding my technical support issues. What a way to support your product and honor your clients. Thank you Cakewalk.

Currently experiencing the same problem. Had to restart because my UAD-2 card bailed on me. UAD works now, but Sonar has this new error. I'll try a few things and post any successful results.

ctrlsurface.dat deletion worked for me!