browse-url-firefox does not work with Firefox Quantum.

If Firefox Quantum is already running, then I am told:

Firefox is already running, but is not responding. To open a new window, you must first close the existing Firefox process, or restart your system.

If Firefox Quantum is not running yet, then the url is opened in the old Firefox version, which I apparently still have installed.

Does anyone know of a new implementation that does? Or knows enough about the new interface to implement it?

  • Works for me on GNU Emacs 27.0.50 (build 15, x86_64-pc-linux-gnu, X toolkit, Xaw3d scroll bars) of 2018-01-11. I have both Debian packages firefox (57.0.4) and firefox-esr (52.5.0) installed. All of browse-url, browse-url-firefox and invoking firefox from the command-line work. What's your emacs-version?
    – Basil
    Commented Jan 13, 2018 at 12:53
  • 2
    Judging from support.mozilla.org/en-US/kb/… it sounds like your system firefox executable, or at least the one known to Emacs' PATH, is pointing to the old Firefox version. The fix could be as simple as adjusting this or setting browse-url-firefox-program to Firefox Quantum's actual executable.
    – Basil
    Commented Jan 13, 2018 at 14:08

1 Answer 1


Turns out browse-url-firefox-program defaults to iceweasel (even in Emacs 26.0.91). Not a very good choice now that even Debian Stable uses the name "firefox" (which it previously didn't do due to legal issues). Not sure why that resulted in the above error, but setting that variable to firefox fixes the issue.

  • As indicated by @Basil in a comment underneath the question by the original poster ... it turns out that this was as simple as ...
    – lawlist
    Commented Jan 13, 2018 at 16:19
  • I did not actually read that far. I got all the way to "... PATH", went on to check there was no issue with that. Everything was good. Then I started building 26.0.91 and went watching tv. When I came back I looked at the function and saw browse-url-firefox-program there. Sometimes two people have the same idea without one of them ripping of the other.
    – tarsius
    Commented Jan 13, 2018 at 17:21
  • Spoken exactly like a copycat! Just kidding; my comment may mention browse-url-firefox-program, but I was actually thinking of a slightly different issue to the one it turned out to be.
    – Basil
    Commented Jan 13, 2018 at 18:37

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