I'm running macOS 10.12.5 Sierra with Firefox 54.0 on a MacBook Air. A Firefox icon is present in the Dock. When launching Firefox from this icon (or double-clicking the icon in the Applications folder), it immediately crashes. However, if I launch it via the command line ($ ./firefox in the app folder), it does not crash. Launching via open -a Firefox also crashes.

I launched Firefox from the command line in safe-mode and disabled all add-ons, but it still crashes when launched from the icon in the Dock.

I'm using the new Compact Dark theme. I disabled this and tested again, but Firefox still crashes when launched from the Dock icon.

Removing the icon from the Dock and adding it back did not solve this.

Downloading a fresh copy of Firefox 54.0 and installing over the previous version of 54.0 did not solve this.

Suggestions to fix this?

Update: This is not resolved in Firefox 54.0.1.

Update: This appears to be resolved in Firefox 55.0.2 (64-bit).

  • 2
    Have you removed the icon from the Dock and added it again? Does it crash when launching the app bundle from the Applications folder? When you run from command line, are you talking about using open or running the binary file within the .app bundle?
    – grg
    Jun 14, 2017 at 10:19
  • 1
    Click and drag the app icon off the Dock and release to remove. Go to the Applications folder and drag the app back to the Dock.
    – grg
    Jun 14, 2017 at 10:22
  • 1
    As grgarside asked, what happens when you double click Firefox from the Finder? Which is the "relevant folder" you mention in your comment? Starting Firefox with ./firefox is not the standard way to start it, but open -a Firefox.app...
    – jaume
    Jun 14, 2017 at 10:27
  • 1
    I was editing my comment when you answered... Which is the "relevant folder" you mention in your comment? Typing ./firefox on the command line is not the standard way to start it, but open -a Firefox.app... How did you install Firefox? Please consider reinstalling as explained at support.mozilla.org/en-US/kb/… and report back.
    – jaume
    Jun 14, 2017 at 10:31
  • 1
    Try deleting all Cache files, preferences, and application support. If you have another user on the computer, try on that user first and see if it crashes. If it doesn't on a secondary user, it's something in your caches/preferences. Uninstalling doesn't actually remove these files so it would persist.
    – Jahhein
    Jun 14, 2017 at 12:08

1 Answer 1


Do the following in a terminal:

cd /Applications/Firefox.app/Contents/MacOS

./firefox &

Firefox 54.0 will launch successfully with all installed add-ons and themes activated.

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