Recently I upgraded Firefox to 77.0.1.I had a tough time importing old bookmarks. Now post upgrade it crashes frequently like once in 4 hours.Also after crash its disappearing completely from system.I cannot find the Firefox.app to open it again.I have properly downloaded and moved it to application folder.Still no idea why this is happening.It's really annoying .I have the .dmg file which I drag and place Firefox.app in Applications folder every time it crashes and it works.But cannot keep on doing that repeatedly. Can some one help on this?