Some quick Sys Info: iMac 27-inch, Late 2015 Mac OS 10.12.3 Firefox v60.0.1, Standard Release (Also confirmed to happen on Developer edition and Nightly) Issue: For a consistent 6 months or so (started before and continued after Quantum update), whenever Firefox has automatically downloaded and queued an update to be installed, the Firefox Updater (and by extension, Firefox) crashes immediately upon launch. There is no error message, nor does it seem to output a message into any sort of text log. The icon simply appears on the dock, bounces once, then disappears. As it stands, the only way to solve this is to manually delete the cached update files in my Library, then use another browser to download an updated copy of Firefox to install over the old installation. Some things I have tried that do *not* solve this issue: Deleting my Firefox profile, Creating a new Firefox profile, Completely deleting and clearing my settings, Fully removing and reinstalling Firefox, Removing all of my addons and plugins, Installing different editions and versions of Firefox, Starting Firefox in Safe Mode, Using the 'Refresh Firefox' feature, Poking around in the files in my terminal like I have any clue what I'm doing. Some things I haven't checked because I'm not smart enough to know how to do them right: Starting updater through the terminal in verbose mode to see if it has a crash error?, Figuring out what file the updater is unpacking into and changing the permissions to be more open, Running the updater as SU (thought this might be a bad idea). I would really like to have my automatic browser updates back and would prefer to not have to dig around in my system files whenever I want to start my browser—if anyone has an idea of what might be causing this, I would greatly appreciate the help!