I tried booting it while holding option/shift to reset preferences and such...but that didn't help. It may be worth noting that this project was transferred from a FCP7 XML file. It has been working fine in every other way...it's just the "looks" filter that causes instant crash.
I had the same issue last year, after CC2017 came out. The issue was Red Giant was possibly caught off guard to changes by Adobe. They responded the same day (about 10-12 hours later) I requested support...Is Magic Bullet up to date? Possibly that is the issue...
A hard solution would be to copy all your custom Looks to a temp folder, uninstall MB, and manually delete any magic bullet folders, restart your computer, then reinstall MB, update, then copy your custom looks back into the correct custom folder. This is what I did when I upgraded to cc2018 upon the advice of Red Giants support staff (I inquired before upgrading).
If you discover the solution, maybe a follow up post to this thread would be helpful to others.