At some point I found myself not being able to go to File > Open in Cubase and open Cubase Project files (CPR extension). They were greyed out for some reason.
In the Mac Finder, Cubase project files were labelled as being of the kind: “RetroArch Content File”.
I had the files associated to open in Cubase 14, but still the Finder window opened inside of Cubase would grey out CPR files so I couldn’t open them.
I had to uninstall the RetroArch application to resolve this.