Installing multiple versions on Mac OS X is basically dragging the Firefox application out of the DMG file to the desktop and rename the folder. You can drag the renamed Firefox application folder to the Applications folder like you would normally install Firefox. You can possibly eject the DMG file and and trash the installer.

You may need to use the terminal to create a new profile for that version.

• https://support.mozilla.org/en-US/kb/profile-manager-create-remove-switch-firefox-profiles

Thanks Dropa and cor-el.

Follow-up question: So I have the release version of Firefox installed on my Mac and I see it in the Applications folder. It's not enclosed inside a folder of its own. Moreover, the Firefox app inside both (release and beta) DMGs is named Firefox.app. So what you're suggesting is copy the Firefox.app from the beta DMG, put it inside a folder on Desktop, rename that folder to say, 'Firefox Beta', and then move that folder to the Applications folder? Or are you suggesting renaming the Firefox.app (taken from the beta DMG) to Firefox Beta.app and then put it in a folder (or just skip the folder since I'm renaming the .app itself) and then move it to Applications?

Thanks!

You can just download, open, and then run it. Then log into it with your Firefox account and sync your data if you want.

I assume that you need to rename Firefox.app to something like Firefox-Beta.app as that is the folder you drag to the Dock.

Nope. Just download, open, and then run it.

I have the Firefox.app (release version) and Firefox.app (beta version) now concurrently installed on my macOS. Since both of them have the same name, I renamed the beta version to "Firefox Beta.app". Now both of them sit alongside each other in the Applications folder. But now, Launchpad, for some reason, shows only one Firefox icon and that is Firefox Beta. Firefox is still accessible from the Applications folder and I can just drag it to the dock, but I can't see it in Launchpad. Any ideas how to fix this? Thanks!

I downloaded Beta and see the issue. Looks like the Dev team does not name it Firefox Beta like Firefox Developer Edition.

Found this...

How do I make an application appear on Mac Launchpad? Luckily, you can add an app to Launchpad fairly easily.

   Open the Finder app on your Mac.
   Navigate to the Applications folder (or wherever your program is).
   Click and drag the app from the Finder window to the silver Launchpad icon on the Dock.
   Release the app.

Hi jonzn4SUSE, did the drag-the-app-onto-the-launchpad-icon thing work for you? It doesn't seem to work for me when I dragged the Firefox.app and dropped it on the Launchpad icon in the dock. Thanks.

Didn't need to try it because it was already there. see screenshot

Decided to check and see if Nightly is installed as Firefox Nightly. see screenshot IMHO Dev dropped the ball when it comes to Beta.

I would suggest you get your google on and find a fix for Launchpad.  ;-)

Or you can remove beta and get the Dev or Nightly version.