Can't open HFCS files anymore

Hi there, it seems that I can open the Mocha plugin from HitFilm 2017 and create tracking data, but HitFilm no longer allows me to import HFCS files.
The HFCS files on my desktop display proper HitFilm type icons, but if I try to open them directly, the main HitFilm app appears but with no project.

Clicking on IMPORT... does not display *.hfcs files or open them.

Thanks in advance