Are you a developer looking for a method that actually works to run multiple copies of Firefox on their Mac? Well I and many others out there used to be able to do this back in the days of OSX Lion but Apple changed things over the years and made it seemingly impossible to run multiple copies of Firefox at the same time. You are wasting your time if you think any of the other solutions and tutorials out there to overcome this actually work, because they don’t and that’s why you ended up here.

A lot of developers like myself need multiple browsers on their desktop, not only for testing web sites but also to have their daily open tabs laid out in front of them all nicely. Firefox is of course the only browser that supports side or tree style tabs which really kicks any other browser in the backside as far as ease of usability goes and which is why a lot of developers like to use Firefox for their daily tasks and need to be able to run multiple copies of Firefox.

But if you are like me and manage anywhere upwards of 20-30 wordpress sites, that already takes up one whole browser. Add to that all my servers administrative interfaces and a bunch of other things I need open in front of me every day and suddenly one browser is simply not enough. Resorting to using other browsers which do not support side tabs is just a pain to say the least.

Well, of all the solutions out there on how to run multiple copies of Firefox on OSX, none of them work. I sat down last year and spent nearly 4 full days figuring this out (I’m a persistent bugger) because it annoyed the hell out of me and my solution to run multiple copies of Firefox on OSX works 100% and works on OSX Yosemite, OSX Mavericks, OSX El-Capitan and even macOS Sierra.

So here we go with the ultimate tutorial to crack past OSX’s restrictions of running multiple copies of Firefox at the same time.

I run 4 different and independent versions of Firefox. One is for all my WordPress sites, One is for all my server related work, One is for my general browsing and the final one is for opening Risky sites which I use to test for bad web sites which get included in my Nginx Bot Blocker. So in this tutorial I am going to show you how to set up 4 versions of Firefox, each with their own profile, their own set of open tabs and they of course are all the same version, can run side by side simultaneously and they all update independently of each other. This is also good because you may have a Firefox extension in one browser that you do not need in another and my solution takes care of all of that.

So ready steady go …. here we go.

Step 1 to run multiple copies of Firefox

  1. Browse to your Applications folder and find your Firefox.app
  2. Right click on Firefox.app and Select Copy
  3. Go to your desktop, right click and select Paste
  4. Rename this application to FirefoxDeveloper.app
  5. Right click on FirefoxDeveloper.app
  6. Browse to your Applications folder and Paste it back there.
  7. Do the same process now for the rest of them, in my case the others are called FirefoxServers.app and FirefoxRisky.app
run multiple copies of firefox on mac osx
Here’s what your application folder should look like – minus the cool new independent application icons of course but read on

Step 2 to run multiple copies of Firefox

  1. Okay so now you want them all to have fancy icons so that they appear differently on your OSX dock
  2. That is now easy, go to this site and pick a few icons you like, make sure to download the .icns version of the file
  3. Go to your documents folder on OSX and make a folder called FIREFOX
  4. Place all your .icns files in the FIREFOX folder you created.
  5. Double click on the icon file you want to use and it will open in preview
  6. Select EDIT > Copy

Run Multiple Copies of Firefox on mac OSX - change firefox application icon

Step 3 to run multiple copies of Firefox

  1. Now go back to your applications folder and right click on one of the new apps you created for instance FirefoxDeveloper.app
  2. Select GET INFO
  3. Click on the small icon in the top left of the Get Info windows and select EDIT > PASTE from the Finder menu
  4. Close the Get Info window.

Run Multiple Copies of Firefox on OSX - Here's How To Really Do It - Change Firefox Application Icon on osx Sierra

Step 4 to run multiple copies of Firefox

  1. Ok so now that new application called FirefoxDeveloper.app has a nice WordPress icon. This is the app I use for managing all my WordPress sites.
  2. Repeat the same process above for your other application copies of Firefox that you created so that they all have their own individual COOL icons.
  3. So now your applications folder will look more like mine with each app having its own cool icon.
run multiple copies of firefox on mac osx
Here’s what your application folder should look like now with each copy of Firefox having its very own application icon.
  1. Okay so now we get a little more complicated because there still is no way to run multiple copies of Firefox, you can prove this by opening your main Firefox.app and then after that trying to open one of your new ones and you will get a nasty error message like below.

Run Multiple Copies of Firefox on OSX - Here's How To Really Do It

Step 5 to run multiple copies of Firefox

  1. Dang it … what do we do now?
  2. Here comes the slightly more complicated part of this tutorial but work through it slowly and pay attention to each step and soon you will have 4 or more independent copies of Firefox running at the same time.
  3. Make sure Firefox is closed and then
  4. Open the Firefox Profile Manager by open Terminal and typing “/Applications/Firefox.app/Contents/MacOS/firefox-bin -P” and press Enter
  5. This brings up the Firefox profile Manager
  6. Create 3 new profiles as I have done in the screen shot below

create multiple firefox profiles and run multiple copies of firefox simultaneously on mac osx

Step 6 to run multiple copies of Firefox

  1. Okay so now we have a profile for each of our new Firefox application copies that we created earlier.
  2. Now you remember we created a folder called FIREFOX in our Documents folder on OSX where we placed our .icns files.
  3. Now are going to create 3 special launchers for each application using OSX Automator
  4. Click on Spotlight and type Automator and open the Automator application

open osx automator and create launchers for running multiple copies firefox on mac osx

Step 7 to run multiple copies of Firefox

  1. Click “Create New Document” and when Automator opens choose “Application” as the type of project you want to create.

create application launcher for osx to run multiple copies of firefox simultaneously

Step 8 to run multiple copies of Firefox

  1. In this case we are creating the first launcher for our FirefoxDeveloper.app.
  2. Drag “run shell script” to the right hand windows and copy the code for running the application, NOTE: you must specify the correct path and the correct profile name to open when using this launcher. In this case my app is called FirefoxDeveloper.app and the profile it must open is called “developer” – See the screen shot below. In my case I have 3 launchers each with their own different command line script as follows:
  3. open -n /Applications/FirefoxServers.app –args -P servers -no-remote | open -n /Applications/FirefoxDeveloper.app –args -P developer -no-remote | open -n /Applications/FirefoxRisky.app –args -P risky -no-remote

open osx automator and create launchers for running multiple copies firefox on mac osx sierra

Step 9 to run multiple copies of Firefox

  1. Now save this application in Documents/FIREFOX/FFDeveloper.app
  2. Do the same steps for your other copies creating a separate launcher for each one as you can see in my screen grab below.

run multiple copies of firefox on osx macos using special launchers created using automator

Step 10 to run multiple copies of Firefox

  1. Now repeat the process from earlier on (Step 2 and 3) to give each launcher it’s own individual cool icon which matches the icon you used for each of the application copies you made earlier.
  2. Keep in mind now we are dealing with different entities here, 3 application copies of Firefox located in the /Applications folder and 3 Launchers we created using Automator located in /Documents/FIREFOX/launcher.app
  3. When you have all 3 launcher icons changed we can now move into the next and final step.
  4. Drag the folder /Documents/FIREFOX/ to the right hand bottom side of your dock as in the image below.

run multiple copies of firefox on macos osx sierra elcapitan yosemite launchers

Step 11 to run multiple copies of Firefox

  1. Now to final steps on how to get your individual Firefox applications to run simultaneously.
  2. One by One click the folder icon you dragged to your dock and open just ONE of the new apps at a time.
  3. When it opens, right click on it and choose Options > Keep in Dock
  4. Here’s what it looks like now with all 3 of your launched versions of Firefox pinned to the Dock

run multiple copies of firefox on macos osx using launchers created by automator

Step 12 to run multiple copies of Firefox

  1. Okay so now you can drag those to anywhere on your dock you like. In my case I have all 4 of my icons next to each other as in the image below.
run multiple copies of firefox simultaneously on osx macos sierra elcapitan yosemite mavericks
Here’s all 4 of Firefox Applications all pinned to the taskbar and all running at the same time – READ NEXT STEP VERY IMPORTANT !!!!

Step 13 to run multiple copies of Firefox

  1. As you can see in the above image I have all 4 applications pinned next to year, all identifiable by their own custom icon and all running at the same time.
  2. There is now however a VERY IMPORTANT method for launching the apps and without following this you will get the dreaded message “A copy of Firefox is Open”
  3. OK … so everyday when your work day begins you start by first opening your main Firefox.app
  4. Thereafter you launch each other individual application copy using the launcher folder on the right hand side of your dock, the image below explains this easily for you and proves without the shadow of a doubt that you can indeed run multiple copies of Firefox on MacOS all at the same time and that you have NOT wasted your time working through this tutorial.

run multiple copies of firefox simultaneously on osx macos sierra elcapitan mavericks yosemite

 

Now you can finally get back to work and have 4 or more individualized copies of Firefox all running at the same time. As mentioned earlier each copy will update itself and it’s plugins if its open when a new update is pushed out. To keep all of them updated you can from time to time just check if there is an update available in each running copy and then update it manually. There really is no limit and you can create as many copies of Firefox you like using my method, I find 4 to be more than ample for all my work though.

I’ve been using this solution for the past 5 months now and it is beautiful and works like a charm and I am now running macOS Sierra 10.12.3 and it’s all still working 100% ….. APPLE PLEASE DON’T FICKIN BREAK THIS AGAIN !!!!

ENJOY PEOPLE !!!!

COPYRIGHT PLEASE NOTE: This method, this tutorial and all images contained within it are copyright to me and this web site only. This tutorial may not be copied, disseminated or distributed in any form whatsoever without prior written permission from me. Any tutorial site wishing to share this solution may share only direct a link to this page with a brief description of what the tutorial is about.

 

 

15 thoughts on “Run Multiple Copies of Firefox on OSX – Here’s How To Really Do It

  1. br0adband says:

    I know it’s been some time since this solution presented itself and I’m grateful for it but I’m having an issue using it with High Sierra, can’t say that THAT is the reason it’s failing of course but here’s the issue for me. Whenever I get to step 10 I’m good but then when I try to execute the command (and this is mine):

    open -n /Applications/FirefoxQuantum.app –-args -P Quantum -no-remote

    I get an error “The action “Run Shell Script” encountered an error: “open: invalid option — P” and I can’t seem to resolve this. If you’re still around and might be able to point out what I’m doing wrong – I am trying to use the Firefox Quantum build for some testing (version 57.0.0 beta 3) and everything else is done without issues: I created the profile for it (Quantum) but I can’t seem to get past that invalid option error. I’ve used the very same line you posted with the necessary alterations (the FirefoxQuantum.app name) and also the profile name (Quantum).

    Kinda irks me whenever some error like this presents itself and then I just can’t resolve it so, any help here would be greatly appreciated.

    And congrats on discovering the solution, it’s definitely awesome – on Windows I can make portable Firefox setups in 20 seconds without issues, I wish macOS could be that easy. 😉

    • Ubuntu Man says:

      Sorry to hear about your hassles. I just upgraded my MacBook to High Sierra and all my multiple versions of Firefox still work as before on Sierra. I have no tested though with Quantum but will have a look at it during the week and see if I can get it working

      • br0adband says:

        I seem to have it working, I scrapped everything and started over completely with a fresh Firefox ESR 52 and Quantum install, recreated the “app” per your instructions and it seems to be functional for now. Not nearly as easy or as useful as Windows is in that respect meaning I can create those “portable” discrete installs in a matter of seconds, but it’s better than not being able to have two copies working independently at all. 🙂

        Thanks for the info and your efforts.

        • Ubuntu Man says:

          So glad you got it working. Yeah I can feel your pain and frustration with macOS ….. it took me almost a whole week to figure out this solution but it’s utter nonsense when it takes mere minutes to do it on Windows systems. Anyhow … I am glad you got it to work :+1:

  2. Kelly says:

    Mojave appears to have broken this, everytime you restart the legacy FF it updates even when you have the preferences in both versions set to not update. Works great in High Sierra. Same FF versions. Not sure where the break is here, tried deleting plists and profiles and repeated it over and over again, still not working.

  3. Kelly says:

    @Troy, if you copied and pasted the lines above the “arg” requires two hyphens before it “–“, auto format makes it one big dash which will not work.

  4. Sebastian says:

    It’s actually much better to let launcher stop.
    So here is my snippet for you:

    nohup /Applications/CUSTOMAPPNAME.app/Contents/MacOS/firefox -P PROFILENAME -no-remote > /dev/null 2>&1 &

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