Project won't open - Cubase LE 10.5

Hi all, at a bit of a loss with this one. One of the projects I worked on for an album won’t open. When I go try to open the project (or the backups), Cubase goes to load the project, but then I’m redirected to the folder where the project and files are situated, with all Cubase files greyed out. Cubase itself opens okay and other projects load fine.

Anyone come across similar? I did move the recording folder onto an external hard drive at one point, but moved it back as Cubase couldn’t find anything, not sure whether this is related?

Many thanks in advance.

Sorry I should probably have said I’m on a MacBook - running Catalina 10.15.7