Locked out of Nuendo after opening on new system

I initialized Nuendo on a new system. It was open and running.
I saved a blank project file. I quit Nuendo.
I double-clicked to open the new project file and now I get this:
Screenshot 2024-05-28 104015

Nuendo is installed in my C: drive like all of my other programs.
How did it become “unavailable” moments after I was already using it?
???

I would just do an install from the Download assistant to fix that.