[How To] Tip: Install multiple versions of Firefox to test before upgrading to latest release

With the recent rapid releases of Firefox, there may be a desire to test the latest release of FF before upgrading to ensure add-on compatibility, etc. There are many ways to go about testing the latest release of Firefox including using portable versions of FF or installing on a virtual machine. This article provides a how to guide on another method of testing Firefox releases – installing multiple (non-portable) versions of Firefox on your computer.

Note: This guide is written for Windows users. However, the same concept can be applied to Linux and Mac OS X; the process is mostly the same with only a few minor variations.

Before We Begin

Before you delve into installing multiple versions of Firefox, there are a couple things you need to do.

Firstly, ensure auto-updates for Firefox have been disabled. The reason you want to disable auto-updates is if you don’t disable auto-updates then Firefox will automatically update you to the latest version of Firefox – overwriting the current version you have – which then nullifies the whole point of testing a new release separate from your main, day-to-day browser.

To disable auto-update in Firefox, go to Firefox Options -> Advanced -> Updates, uncheck Firefox, and click OK:

Secondly, you have to make a decision. Do you want the test versions of Firefox (the latest releases you will test before upgrading your main FF install) to access your add-ons, bookmarks, etc.? If yes, then you don’t have to do anything else — proceed to the next section in this guide. However, if no (i.e. you want to keep your main FF data separate from your FF test installs), you need to create a new profile for each of the versions of Firefox you will install.

To create a new profile you need to launch Firefox’s Profile Manager. First ensure Firefox is closed. Then, to launch the profile manager, press Win + R on your keyboard, type firefox.exe -p in the Run window that pops open, and press OK:

(Note: You may have to type the full path to Firefox if it cannot be found simply by typing firefox.exe, e.g. you may need to type C:\Program Files\Mozilla Firefox\firefox.exe -p)

Once you press OK, Profile Manager will open:

From the Profile Manager click the Create Profile… button and create a new profile:

Make sure to change the name of the new profile to something that is relevant to the version of Firefox you are installing, e.g. if installing Firefox 9 name the profile FF9.

Once you hit the the Finish button, you will be taken back to the Profile Manager. Repeat this new profile process for each version of Firefox you plan on installing. Close Profile Manager after you are done.

Now that you have a new profile created for each Firefox version you plan on installing, you have another decision to make. By creating a new profile you have ensured the new Firefox installs won’t mess with your current Firefox data. However, part of the process of testing a new Firefox release is making sure your add-ons work, right? Therefore you may still want new Firefox installs to have access to your data but at the same time ensure any changes made with new Firefox installs don’t affect your current/main Firefox install. This can be accomplished by copying the data from your current Firefox’s profile into the new profile(s) you just created.

To copy profile data, press Win + R on your keyboard, type %APPDATA%\Mozilla\Firefox\Profiles\ at the Run window that pops open, and click OK:

Once you click OK the folder where Firefox profiles are stored will open:

Double-click on the folder named xxxxxxxx.default (with the xxxxxxxx being random numbers and letters — it is different for everyone). Once inside the xxxxxxxx.default folder, select and copy everything (easiest way is to press Ctrl + A and then Ctrl + C on your keyboard). Now go back to the main Firefox profiles folder and double-click on the folder of the new profile you just created. In my example, the new profile folder is named uc9ngzet.FF9 because I named the profile FF9. Once inside the new profile’s folder, paste everything you just copied (easiest way is pressing Ctrl + V on your keyboard). You may be asked for administrator access to paste some files — give it.

Repeat this process for all the new profiles you created. Close the Firefox profiles folder when you are done.

Once you have done all that is mentioned above, you are ready to begin installing multiple versions of Firefox.

Installing Multiple Versions of FireFox

To install multiple versions of Firefox, do the following:

  • Download the version of you Firefox you want to install.
  • After the download has finished, run the installer.
  • Install like you normally would install any program expect for a few things:
    • First, make sure to select Custom when asked for Install Type:

  • Second, when prompted to select Install Location, change the Destination Folder to anything except the default C:\Program Files\Mozilla Firefox. I suggest placing it in a folder named after the version of Firefox you are installing, e.g. if installing Firefox 9 place it in C:\Program Files\Mozilla Firefox 9:

  • Third, make sure to not create a shortcut on your desktop or Start Menu because it will override your existing Firefox shortcuts:

  • Fourth, make sure to not make this new install your default browser:

Repeat this process for all versions of Firefox you want to install.

After installing all versions of Firefox you desire following the method described above, you are almost ready to begin testing them — there is just one more thing you need to do.

Last Step — Adding Command Line Arguments

By default Firefox is set to do two things: A) Use the default profile in the profiles folder B) Not allow users to run more than one instance of Firefox at a time. To remedy both issues (i.e. to force each new install of Firefox to use the profile specifically created for it and to be able to run multiple versions of Firefox at the same time, to make for easy comparisons) we need to launch new installs of Firefox with command line arguments.

Note: If you opted to not create a new profile for new installs of Firefox you need not worry about the first issue. The second issue is still of concern, however, so don’t stop reading this guide!

Command line arguments not as scary as they sound. In context of what we are talking about, they are simply text commands that modify how a program launches. They require no special expertise or knowledge to use and are extremely easy to implement. If you are confused (or scared) don’t be — the famous dotTech screenshot method of instruction will hold your hand every step of the way. (Yes, I made up that name on the spot.)

To launch new Firefox installs with the relevant command line arguments, do the following:

  • Open the folder where you installed the new version of Firefox. In my example, that is C:\Program Files\Mozilla Firefox 9.
  • Right-click on firefox.exe, go to Send To, and click on Desktop (create shortcut):

  • Go to your desktop and look for the shortcut you just created — it should be named firefox – Shortcut:

  • Right-click this shortcut and go to Properties:

  • At the Properties window look in the Shortcut tab where it says Target. In the Target box at the very end type -P “Profile Name” -no-remote with Profile Name being the name of the new profile you created earlier for this specific version of Firefox. For example, I would type -P “FF9” -no-remote. If you opted to not create a new profile, just type -no-remote. Make sure to put a space between the existing content and the new commands you are typing in. This is how it should look when you are finished:

  • Next go to the General tab and rename the shortcut to Firefox X, with X being the version of Firefox the shortcut is for, e.g. Firefox 9:

  • Click OK to close the Properties window and apply both changes you have made.

Repeat this process for all versions of Firefox you opted to install.

After you have added the command line arguments, you are good to go. You can now start testing the new versions of Firefox you installed. Take note, however, to always launch the Firefox installs via the desktop shortcut. If you launch them from anywhere else then they may not launch with the proper command line arguments and you will have problems.

When Uninstalling…

Eventually you will (hopefully) reach a point where you decide you no longer need the extra versions of Firefox; so you will uninstall them. You can uninstall the extra Firefox installs like you normally would but make sure to not remove Firefox personal data and customizations:

Also if you use a third-party uninstaller, like RevoUninstaller, be sure to not delete any leftover registry entries and leftover files.

If you do any of the above two – i.e if you remove FF personal data and customizations and delete leftover registry entries/files – you will be in a world of digital hurt.


There is no need to update Firefox just because Mozilla says so. You are more than within your rights to update when you feel comfortable with the new release of Firefox. This guide provides a method to safely test new releases of Firefox before upgrading your main Firefox browser. Enjoy!

Feel free to post any comments, feedback, tips, criticism, etc. in the comments section below.

[Thanks hatman for the inspiration behind this article.]

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  • Ed

    Oct. 2015 – Worked well on Windows-7, no problems. Have FireFox 28 that I like a lot and didn’t want to effect it when I needed to update to FireFox 41. Thank you for the comprehensive step-by-step directions…a lifesaver.

  • RobCr

    I posted this on one of Ashraf’s other threads, and suggested that he pass it on (post it) on threads where dotTechies were wishing multiple FF’s.
    Apparently he has not taken my suggestion (he does that a lot).
    If you do a Google for Comodo IceDragon, and go to Comodo’s site, they have a free version of FF. It is identical, except there are a couple of optional Comodo security options.
    When installing it, there is a checkbox allowing it to be portable. If you create a folder and ‘install’ the portable one there, you can then later copy the folder, and create many copies. I have done that. There was slight cross pollination, which I believe can be avoided if you have a rule of never running two versions at the same time.
    In addition, I ran the installer again, and did not tick the checkbox, making that version a proper install. I have just finished using that for an hour, and closed it. Then opened up one of my portable versions, to ensure that there was no cross pollination. It was fine.
    PS You can also install all of the FF extensions, etc.

  • Abhishek

    Thanks so much, Ashraf! This article solved a very important issue for me.

  • Sergey

    Hi, Ashraf!
    Great thanks to you for this great instruction. Extremely helpful!

  • Nice tutorial, that what I was looking for. How to do the some think to other browsers?
    @Rational Db8
    –no-remote: Give you the ability to run two different profiles in parallel.
    -P: To specify the profile name you want to lunch.

  • Rational Db8


    Ashraf, one other note – there is some point at which profiles/bookmarks are handled differently in firefox. I think, but am not certain, that it’s in the switch from v3 to higher versions. Someone will have to check for the actual breakpoint that way.

    Anyhow, in the past on a different tech forum, when I wanted to keep my old version but try a newer one, I was told that sharing one profile could corrupt it, because of the switch in how FF stored/saved/recorded profiles… and that I needed to use two different profiles. I wish I recalled the exact details, but wanted to note it so folks could check it out if they plan on trying to use one profile.

    Of course, here I am, using the same profile in trying 9.0.1 vs 14.0.1, but I’m hoping this won’t be a problem and that the ‘newer’ way of handling profiles/bookmarks is the same after that earlier switch point (which I’m certain was before v9!)

  • Rational Db8


    Hi Ashraf,

    Excellent tutorial – thank you!!

    Might I suggest that in the command line section, explain what the -no-remote addition does. Also, add a screenshot of how the addition ought to look for those who chose to use the same profile for both FF versions. This would eliminate possible confusion – for example, I wasn’t sure if I ought to add “-P -no remote” or if the “-P” was only added if a new profile was specified. I wound up adding just the “-no remote” bit and hope that works when I try to launch in a minute!

    Again, thanks so much for your clear and easy to follow tutorial!

  • this comment is just to get notified of follow-up comments, since I missed it on the earlier one. (SORRY)

  • @Everyone :
    I followed every single step, JUST AS SAID ABOVE; but at the end my new installation has replaced my older one. I installed FF 12.0b4 on top of FF 3.6.13, but now I’m not able to launch the 3.6.13 version of firefox. I even tried executing directly from the “ProgramFiles” folder, but still only the 12.0b4 version launches. So, could you please point out, where might I’ve gone wrong or missed something??? Thanks.

    PS: I’m trying this on WinXP SP3

  • Thank you a bunch for sharing this with all people you really recognise what you are speaking about! Bookmarked. Please additionally seek advice from my website =). We could have a hyperlink alternate agreement between us

  • Era

    gracias !

  • hatman


    I did disable updates. I’ll have to read through the directions a few more times.

  • Ashraf

    @Jacal: You are welcome!

    @Fred: Yep, Returnil will undo any changes made, including FF updates.

    @Mario: Utilu… I’ve heard of that before but never gave it a try myself.

    @Rob (Down Under): LMAO

    @Jacal: Interesting link… thanks!

    @Giovanni: Or you could use Add-on Compatibility Reporter: http://dottech.org/freeware-reviews/25769/firefox-add-on-compatibility-reporter-allows-users-to-run-incompatible-add-ons-in-firefox/. Thanks for the tip though.

    @Ben: Interesting, I didn’t know about the new Profile Manager. Thanks!

    @jayesstee: You are welcome!

    @Don Villas: Hmm… I haven’t tried it myself but in theory it should work just fine. Not sure why it doesn’t work for you.

    @Rob (Down Under): Erm, never used Pale Moon myself so I can’t be of much help.

    @hatman: Lmao we are on the article you are linking. o_O

    @Rob (Down Under): Re: PS I have solved my wee Google search box opening in a new Tab, if anyone is interested — hmmm?

    @hatman: Did you make sure to disable auto-updates? Make sure that is the first thing you do when you run a new Firefox.

  • hatman

    I followed directions. Not sure what went wrong. I have Windows XP pro SP3. Every time I opened a Firefox profile in my profile manager,it updated to Firefox 9. I reinstalled 3.6.25 before opening my main profile so that it would not update.

  • Rob (Down Under)

    Reporting back as promised.
    After running your portable Pale moon, and installing extensions etc.
    Close it, and copy the folder somewhere.
    Rename the folder.
    I also renamed the exe and the ini (same name as the exe).
    The latter may not be necessary, but what the heck.
    When you run that latest folder, you will find that you have inherited the extensions etc.
    (That avoids you having do things twice)
    They both can remember their own Tabs, which is great.
    I would never run the two at the same time, as the Tabs do appear to get confused (or perhaps it is the 70 year old in front of the PC ?).

    I just fired up FF, and it has remembered it’s own Tabs.
    I will probably follow my rule and not run that at the same time as any of the Pale Moons. (Being an old woman again)

    PS I have solved my wee Google search box opening in a new Tab, if anyone is interested ?

  • hatman

    @Rob (Down Under):

    Pale Moon won’t interfere with Firefox. You can install it normally without putting it in a folder. Instructions at link below may also work for “Pale Moon” browser. I have not tried it.

    [How To] Tip: Install multiple versions of Firefox

  • Rob (Down Under)

    If you wish multiple Copies of FF because you wish different versions, then read no further
    For those interested in having multiple copies of FF (all say ver 8), then read on
    I am terrified of stuffing up my main FF, so I have done the following
    I have download Pale Moon browser PORTABLE ver 8
    It is based on FF, but has superfluous features stripped out of it, to make it faster than FF
    The portable version does not need a suite to run it (like some I know of, and dislike).
    You just create a folder in your C drive, and place it in there.
    No Installation. It will just run self contained in that folder.
    It is very zippy (fast), and my FF is unaware of it’s existence (FF Tabs etc are all fine).
    There is an option to download a thingy to copy your FF profile, but me being an old woman, don’t want them even knowing about each other, so I skipped that.

    I like to keep Tabs open from previous session, so they do tend to accumulate.
    (My Main FF has way too many Tabs open)
    I am about to image my drive, and then try to create multiple Pale Moon folders
    If they can run blissfully unaware of each other, then I will have one for say ‘Adult’ stuff, and another for Programming, and another for ……
    I will report back, in case anyone else has a similar desire.

    PS NoScript and unMHT installed fine.
    PPS My FF on my main PC has the wee Google search box top right.
    So when in a web page, I can type something up there, and it opens up a full Google search page.
    In one PC it does that into a new Tab (which I love)
    In my other PCs both FF and Pale Moon load it into the current Tab (which I hate)
    Can anyone advise how to get it opening a fresh Tab ?

  • Don Villas

    “There are many ways to go about testing the latest release of Firefox including using portable versions of FF . . . ”

    Hmm! I just wonder if anyone has ever tried this. In my case the consequence was pretty destructive. I have been using FF8 portable for a while. In an altogether different location on the same Wi7/32 PC I tried FF9 portable. On exit and return to FF8 portable I discovered the following total wipeouts:

    – previous tabs
    – pinned tabs
    – two customised, additional toolbars
    – all bookmarks
    – all add-ons

    Absolutely infuriating!

    Same experience with an XP machine

  • jayesstee

    A very thorough, professional article; with aspects I hadn’t even thought of. Always glad to learn. I bow to the Boss!

  • etim

    @Jacal: Thanks for that link–lots of good info there–answers a lot of my “what’s that option for?” questions without me having to click on the option to see what it does (and hoping nothing terrible happens)

  • Ben

    All of this can be achieved through a much easier process by using the standalone profile manager created by Firefox devs. https://developer.mozilla.org/en/Profile_Manager This will be replacing the built-in profile manager soon. You can manager different firefox versions and profiles much easier with it. Screenshot: http://i53.tinypic.com/nbp0ft.png

  • Giovanni

    To force FIREFOX installing incompatible extensions on a new upgraded Firefox version, just have a look at these nice tips:



  • Jacal

    Firefox is a stable and reliable browser, that should not crash etc. And here is a superb guide:

    Tweakguides – Firefox

  • Rob (Down Under)

    Ashraf asks that you DO NOT Install these on Xmas Day.
    He has generously committed to visit each of our homes and fix any problems.
    He has other commitments on Xmas Day, and that is why you should not try this on Xmas Day

  • Mario

    I tried this procedure once and quit. Now I just use Utilu, and upgrade it from time to time. It installs all existing and not yet existing Firefox versions that you want. Current version 1.0.69 goes from Firefox version up to Firefox Nightly ( but I think they might update it soon, because Firefox 9 is already out and they have only it on the beta 6). They have a similar utility for IE ( from version 1 to 8 )
    See on http://utilu.com/

    mario from brasil

  • Fred


    I tried that when updating to FF v4. Didn’t work. Had to uninstall v4 re-download v 3.6 and install that. The real lazy way is use a program like “Returnil System Safe Free 2011”. With regard to using Returnil to return FF version to the one previously used, Ashraf said, “…@Fred: Yeah, easily. Just turn on Returnil’s disk protection before upgrading and ensure in settings Returnil is set to drop all changes upon reboot.


  • Jacal

    Thanks! It works nicely on beta, aurora and nightly in a XP virtual machine.
    (And I am avoiding work today.)

  • Ashraf

    @etim: Hmm… yeah, that’s not what the cool kids do.0 :-P

    @hatman: You are welcome!

    @hatman: Did you go back and re-download the older version?

  • hatman


    I am using Windows XP. I previously lost my old version even though I set a restore point.

  • hatman

    Thanks for this Ashraf. You have covered some things I never thought of. Will have to be careful doing the installs.

  • etim

    I think I’ll be lazy and just set a restore point to go back to if I’m not happy. Not nearly as slick, but like I said, lazy.

  • Ashraf

    @Steven: You are welcome!

    @Everyone: I did a quick update to this article to add instructions on when uninstalling.

  • Steven

    I was just thinking about how I’d like to try out the beta and alpha releases but was concerned with them not having add-on compatibility… seconds later I saw your latest topic. Thank you! I’ll have to give this a go. :)