I'm disappointed and frustrated.
I've done a clean install of my IMac, I've contacted the support, sent the clip, sent the crash report and still have no possibility of exporting a single frame.
Either I get a warning "unable to initialize" or Hitfilm simply quits.
Looks like I'm not the only one experiencing this problem and the answer is "sorry, we cannot reproduce this issue".
I cannot accept that and hope for a solution asap.