fcpx 10.0.9 fonts arnt all there and fontbook wont work help me

so first off i have fcpx 10.0.9 and i have a older computer so idk if i can update it and i dont wanna risk losing my edits i have already had to re edit everything once so please dont tell me i need to update because thats no help.


i used to have all my fonts it my editor but now there mostly all gone and i have downloaded some new mac friendly ones and font book wont work i am almost 3/4 done and i need to put titles really bad any help is much appertained