I just spent over two hours meticulously unwrapping a complicated mesh and to my dismay, RizomUV froze up on me, after I tried to flatten all islands. I waited over an hour hoping/praying it would rectify itself, but to no avail. Unfortunately there was no option to save the project, only whether I wished to leave, since RizomUV was "still working". So my last resort was finding some Auto-Save option or file, however that also wasn't available.
I realize in hindsight I should have periodically saved my project, however I think having an Auto-Save feature or at least the option to save a project should be available, especially if one's project freezes up.