I suspect you have the same problem as https://support.mozilla.org/en-US/questions/1265998

bgcasey said

Firefox crashes at startup. I'm in a macOS beta program and the crashing begun immediately after a recent OS update on 8/2/19. I've tried wiping all application files and reinstalling Firefox, but it continues to crash at startup. Crash ID: bp-79eb6f5a-fc88-4d32-ae51-231e70190804

danielhelou And ?

still crashing. same situation

You did not say that. Is your computer a Mac running Beta? If so, see https://support.mozilla.org/en-US/questions/1265998

Apple just released an OS update for its beta progam. FireFox now opens without issue.

Good to hear. Well done. Please flag your last post as Solved Problem as this could help others with similar problems.