This means I can’t work on this project until the issue is fixed, and I’m on a deadline.
There is another thread about this right now.
Sad, very sad.
So you already applied the Sonarworks update that supposedly fixes this issue?
Something to try…
Just recently saw a few posts where is was mentioned that they were able to get their project to open if they opened it with an existing project already open. Don’t activate it until after it is open.
Regards 
Yes I had the latest Sonarworks update already 4.2.1.
Prock, unfortunately this didn’t work for me.
What HAS worked: new empty project and importing all the tracks over from the problem project.
Tracks are disorganized but at least I got em!
Still need to understand what the cause of this issue is, to prevent such sticky situations in future.