Time to make the switch to 64-bit Firefox on Windows

Martin Brinkmann
Jan 27, 2017
Updated • Jan 28, 2017

The story of 64-bit Firefox on Windows is a long and complex one, and it is just about to end with Mozilla moving from offering 32-bit Firefox as the default download option to offering 64-bit Firefox on Windows by default.

Mozilla Firefox is offered as a 32-bit and 64-bit version on Windows, with 32-bit still the default right now when it comes to downloads.

While the 32-bit version works well, and it is the only option for systems without a 64-bit processor, it is the 64-bit version that users should consider using if their device is equipped with a 64-bit cpu.

The reason is simple: more RAM becomes available per process that Firefox uses, and 64-bit applications benefit from security features that 32-bit applications don't.

firefox 64-bit

The one downside that may have kept Firefox users from switching to 64-bit was limited plugin support in the 64-bit version of the browser. It only supports Flash and Silverlight. That restriction is still there, but with Mozilla throwing out NPAPI plugin support soon -- with the exception of Flash -- that is no longer an argument if you want to stay with a recent build of the browser.

Chance is, that you are still running a 32-bit version of Firefox as you'd have to get out of your way to grab the 64-bit installer from the Mozilla website.

Back in July 2016, only 1.7% of Firefox users on Windows used a 64-bit version of the browser. That's not much. The number has probably gone up til then, but it is likely still low due to Mozilla prioritizing the 32-bit installer over the 64-bit currently.

I explained how to upgrade from Firefox 32-bit to Firefox 64-bit here, and suggest you check out the guide for a full rundown on how to do that.

Good news is that it is super easy to upgrade Firefox from 32-bit to 64-bit. All that is usually required is to download the dedicated 64-bit installer from Mozilla, and run it. All your shortcuts, profiles, bookmarks, modifications and so on will continue to work.

Note: The 32-bit version is not uninstalled automatically. I suggest you keep it around until you have worked with the 64-bit version for a while. Once you are confident that there are not any issues, you may remove the 32-bit installation of Firefox from your system.

Check the CPU

operating system 64-bit

First thing you do, is check if you can update Firefox to 64-bit. USe Windows-Pause to open the System Control Panel applet. Find the "system type" listing on the page, and check whether it says 32-bit or 64-bit.

You need a 64-bit processor. If your system does not have one, you are stuck with 32-bit Firefox. Don't worry though, Mozilla won't end support for 32-bit, but will just focus on distributing 64-bit Firefox over 32-bit in 2017 and later.


firefox profiles

Second thing that you do is back up the Firefox profile folder. Type about:support, click on the show folder link to open it on your system.

Note that this opens the profile that is in use at the moment. Go up two directories, so that you are in the main Firefox directory under the user folder.

Select profiles, press Ctrl-C to copy it to the clipboard. Now browse to another folder on your computer, and use Ctrl-V to place a copy of it in it.

The 64-bit upgrade

firefox 64bit download

This is without doubt the easiest part. Download Firefox Stable, Firefox ESR, Beta, Developer or Nightly from Mozilla.

Make sure you pick the 64-bit version for Windows. It is indicated by a 64-bit icon on the download icon.

Make sure you close Firefox before you continue.

Run the installer afterwards, and follow it through to the end. Firefox will be upgraded to 64-bit.  You can verify that using the method mentioned above.

Now You: Do you run a 32-bit or 64-bit version of Firefox?

Time to make the switch to 64-bit Firefox on Windows
Article Name
Time to make the switch to 64-bit Firefox on Windows
With Mozilla retiring NPAPI plugin support in 2017, it is time to upgrade 32-bit versions of the Firefox web browser to 64-bit versions.
Ghacks Technology News

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  1. Holly Bates said on September 26, 2017 at 2:47 pm

    I think portable version works great at moment.

    Firefox Portable [Latest]

  2. George said on July 21, 2017 at 6:50 pm

    I switched from 32 bit to 64 about a month ago and haven’t had any issues for the moment. I did noticed that Java is not supported in the 64 bit version. Why is this and how can this affect me??? I have Windows 7-64. Just curious and should I go back to the 32 version or am I safe using the 64 bit version?

    1. A different Martin said on July 21, 2017 at 7:26 pm

      I think Mozilla made a (security? performance? stability? maintainability?) policy decision to support as few plug-ins as they could get away with in Firefox x64, even when x64 plug-ins are available.

      For what it’s worth, Java is supported in Pale Moon x64, whose interface is like pre-Australis Firefox and which supports the classic (XUL/XPCOM) Firefox type of extension. It’s still my default browser, but some people are worried about its long-time viability once Mozilla kills Firefox support for XUL/XPCOM extensions this fall. I guess it will depend on how many Firefox users switch to Pale Moon, encouraging XUL/XPCOM extension developers to continue working on them.

  3. Max said on March 3, 2017 at 1:26 pm

    It sucks, no Java support in 64bit. I wish Mozilla would quit playing Microsoft style politics and start delivering what customers want. No wonder people are leaving Firefox in droves. I have to run 2 browsers with different interfaces just to get Java support. Much easier to just switch to a browser that supports it.

  4. Chris said on January 29, 2017 at 8:28 am

    “The reason is simple: more RAM becomes available per process that Firefox uses, and 64-bit applications benefit from security features that 32-bit applications don’t.”

    Martin, can you write an article about the 64-bit security benefits for Firefox, as well as any flaws, as mentioned in the comments above (by Dan82 and others)?

    1. CHEF-KOCH said on January 29, 2017 at 7:09 pm

      The article already exist, which explains why 64 bit is more secure:http://www.howtogeek.com/165535/why-the-64-bit-version-of-windows-is-more-secure/

  5. 4whichpurpose said on January 28, 2017 at 9:09 pm


    Is there some NASA page with images bigger than 2 GB?

    1. Rick A. said on January 28, 2017 at 11:56 pm

      “Why”? Because most people don’t live in the past.

  6. matt said on January 28, 2017 at 6:45 pm

    Typo in article I think:
    “Chance is, that you are still running a 32-bit version of Windows as you’d have to get out of your way to grab the 64-bit installer from the Mozilla website.”
    Pretty sure you mean to say ‘you are still running a 32-bit version of Firefox’…

    1. Martin Brinkmann said on January 28, 2017 at 9:16 pm

      Matt you are right, thanks!

  7. Tophebet said on January 27, 2017 at 9:35 pm

    Thank you, Martin Brinkmann. I switched to 64-bit Firefox this morning. When three plugins (OpenH264 Video Codec; Primetime CDM; and Wildvine CDM) failed to install promptly, I clicked on the gear icon on the Firefox about:addons page, and then clicked on “Check for Updates”. The plugins installed right away.

  8. Anonymous said on January 27, 2017 at 8:44 pm

    Let me get this straight. Add-ons don’t work but it’s time to switch??

    1. Martin Brinkmann said on January 27, 2017 at 9:26 pm

      Add-ons work, most plugins don’t.

  9. megazoid said on January 27, 2017 at 8:34 pm

    I installed and used it and it ran great until I tried to login to Protonmail.com. Firefox crashed every time i tried to open Protonmail.com.
    I had to go back to the 32 bit Firefox. I was running the latest release. Crash report sent to Mozilla for evaluation.

  10. XenoSilvano said on January 27, 2017 at 6:04 pm

    I went to Firefox’s about page hamburger icon > ( ? ) > About Firefox
    there is states that I am currently running Firefox 51.0.1 (64-bit) ‘Portable Version’ 😜

    @Xan – I would very much like to see that bench mark

    1. PeaceByJesus said on January 30, 2017 at 3:51 pm
    2. Xan said on January 27, 2017 at 6:39 pm

      It’s dated back to Firefox 42. Includes WaterFox too.

      I think Firefox 64 is now used by about 7% of users and speed differences should be reduced.

      I’m switching to 64 in a few months

  11. MdN said on January 27, 2017 at 4:06 pm

    64 bit on Xubuntu, no problems with crashes or RAM usage, only Pale Moon is somewhat lighter but not in all situations. Used to sometimes freeze back in the day when I was still on Windows and used AdBlock Plus, but that was several years ago. “Script not responding”? NoScript or uBlock or uMatrix.

  12. CHEF-KOCH said on January 27, 2017 at 3:40 pm

    X86 in 2017 – seriously what year is it? … :oP

    1. Chains The Bounty Hunter said on January 28, 2017 at 7:45 pm

      Apparently it’s the mid-to-late 90s based on the style of emoticon you’re rockin’ there, CHEF-KOCH.

    2. Earl said on January 28, 2017 at 3:49 am

      Do you really want to use a computer w/o backward compatibility? (It’s just a name.)

  13. Anonymous said on January 27, 2017 at 3:28 pm

    The thought of my 200+ tabs running as multiple processes makes me cringe.

    1. Jeff-FL said on January 27, 2017 at 8:45 pm

      why in god’s name would any sane person have 200 tabs open?

      1. CNN = Fake News! said on August 5, 2018 at 8:37 pm

        Why not? I’ve had 1,611 tabs open in Firefox before… Older version…
        Modern Firefox takes 200 mb for 1 blank tab open, vs early Firefox taking 30 mb for same.
        x64 Firefox sucks more RAM down than x32.

        Internet Explorer: Crashes around 15 to 25 open tabs (unstable) no matter the version
        Chrome: Can also open hundreds of tabs without a problem, but needle thin tabs are a pain!

        1 tab at a time is not an efficient way to test, search for answers, etc…

      2. Anonymous said on March 10, 2017 at 1:46 am


      3. Jim said on March 1, 2017 at 10:32 pm

        Wondering the same thing.

      4. Rob said on January 30, 2017 at 6:18 pm

        Didn’t you know? Once you close the tab, the site no longer exists. Therefore, it all has be recreated again and it’s different each time you go to it.

        I’m being facetious, of course. Some people don’t understand how the web works, even in 2017. Sad sad sad.

      5. PeaceByJesus said on January 30, 2017 at 3:44 pm

        I have two profiles of Firefox running with over 200 tabs open on each, 28 per row (because unlike most other browsers, TabMixPlus enables multiple rows and reducing tab width), identifiable (Colorful tabs and the FT DeepDark theme helps) and different sessions are saved using Session Manager. And with a 23”’ monitor there is plenty of space (which would not be the case if could not customize as Firefox extensions enable).

        Sample of tab rows: https://www.flickr.com/photos/14822395@N03/30806645076/in/dateposted-public/

        The main functional reason for so many tabs is that in one browser, besides pages like for weather and site stats, etc, there are multiple forums threads I check or want to get back to and research sources (mostly Christian related, thus the “God’s name” aspect) related to that which I want to read (and I am less likely to do so if i just bookmark them rather than leaving them visible), etc. And of course there are some that I forgot to close.

        The other browser is mainly for shopping various items, for myself and others. and tech related research, which includes this. And with 16gbs ram, and a 4.2 cpu in W/10 64 bit, you can see what i am interested in 64 bit. I also have Cyberfox, Pale Moon and Chrome installed, plus IE and Edge, but the latter 3 are vastly inferior for what I want to do. Thank God for Firefox.

      6. Rick A. said on January 28, 2017 at 12:44 am


    2. Denizen said on January 27, 2017 at 5:55 pm

      That’s still only 1 content process in Firefox 51. And 8 in the highest case I’ve seen considered so far. Not 200 processes :)

  14. Mike O said on January 27, 2017 at 3:23 pm

    I had used Firefox from day one. Several years ago I tried Pale Moon and liked it. Eventually however, I was forced to switched back to Firefox a year or so ago after some banking sites complained the Pale Moon browser was seen as a dated browser and would not allow access. Last week after getting completely fed up with the now all too frequent freezing and “Fiirefox not responding” messages I returned to Pale Moon. I enjoy PM’s starts faster, faster site load time, and no more issues with my bank sites. Best of all no more browser messages telling my browser is not responding.

    1. Xan said on January 27, 2017 at 3:30 pm

      Never ever get those even on this 8 years old computer or that lame smartphone. I wonder if some plug-in or extension caused an issue, e.g. antivirus shit that would not exist in Pale Moon, or if it’s malware or crapware plaguing your Firefox install and not caring about Pale Moon, or if it’s a Firefox bug triggered on your specific system.

  15. Dan said on January 27, 2017 at 2:59 pm

    Just another guy that’s been using Cyberfox 64bit for almost a year now.

  16. hah said on January 27, 2017 at 2:14 pm

    I have been using FF x64 from day 1 it start offering.

  17. EdDataFix said on January 27, 2017 at 1:25 pm

    Doesn’t support Google Voice. Tried I few things and 64 just won’t work with Voice.

    1. A different Martin said on January 27, 2017 at 7:52 pm

      Lack of Google Voice support is a dealbreaker for me, too.

    2. jasray said on January 27, 2017 at 5:07 pm

      Had the same problem–pointless for me to use a browser that doesn’t support Google VoIP.

      On the same note–sort of–how can I get Firefox 32 to stop auto updating? I’ve turned off all of the “update auto” boxes I can find, but FF still updates itself, creates a new profile, and takes a chunk of time to get it back to “normal” for me.

      Now, Cyberfox–it’s a nice build, and I use it as the main browser.

      1. Denizen said on January 27, 2017 at 5:47 pm


        Google Voice ain’t working because it requires a plug-in, doesn’t it ? I don’t use it so I wouldn’t know, I’m just surprised that Google doesn’t provide a web standards compliant alternative considering plug-ins are on their way out in all browsers.

  18. Deana said on January 27, 2017 at 1:09 pm
    1. HK-Rapper said on January 27, 2017 at 7:43 pm

      Except the tech-literates managed to get it running without an issue.
      Whoa big surprise you need x64 flash for x64 Firefox. *shake my head*

  19. Karl O. said on January 27, 2017 at 12:47 pm

    Hi guys,

    I strongly advice you to NOT run 64bit firefox. Simple reason (which only know a few guys on bugzilla):

    There is still a ‘zlib regression’ on 64bit firefox which is something similiar to memory leak. After a random amount of time passing by there will be suddenly a huge, unstoppable CPU and RAM consumption.

    Therefore if you an extreme user using hundreds of tabs, your workflow will break.

    1. Ben said on January 28, 2017 at 11:23 am

      Could you link the ticket? I cannot find one.
      But since I need the memory for all my open tabs I cannot switch to 32bit anyway. This is why I switched to 64bit when it came out two years ago or so.

  20. Dwight Stegall said on January 27, 2017 at 12:25 pm

    Martin: I wish you’d do an article on a Chrome clone Iron Browser from Srware.net

    It has a lot less Google tracking in it and works just as good as Chrome. There are both 32-bit and 64-bit versions. It has a profile backup and restore utility that works as advertised. I’ll never use Chrome again.

    1. Kubrick said on January 27, 2017 at 9:22 pm

      There is nothing to be gained from using iron.All you need to do is untick a few boxes in chrome and it achieves the same thing.It still connects to google servers upon starting and its source code has been blocked.I would sooner use chrome than srware iron.

    2. Martin Brinkmann said on January 27, 2017 at 1:30 pm

      I reviewed it back when it first came out ;)

  21. Jojo said on January 27, 2017 at 11:39 am

    Had me in “Time to make the switch to 64-bit Firefox on Windows”
    Lost me in “The reason is simple: more RAM becomes available per process that Firefox uses”

    And thank u @Dan82 for the good warning, saved me the question and a quest :)


  22. TT said on January 27, 2017 at 11:23 am

    Google Hangouts still not working.

    1. Rob said on January 30, 2017 at 6:09 pm

      LOL…at first I read that as Google “Handouts,” which I believe would be a really cool app.

  23. Dan82 said on January 27, 2017 at 11:23 am

    I agree that using Firefox as a 64bit version means the browser *can* use more RAM, but in my opinion this is not necessary or advisable in most usage scenarios. The 64bit browser does not work automatically better than its 32bit variant, but it uses about a third more RAM for the same function and user experience anyway. This does require you to have that amount of memory available merely to keep the browser working the same as before – and if that’s not the case, then the switch will make the browser slower. For that reason I would hesitate to even call the ability to draw more RAM per process an advantage in the first place, because the time I spent using Firefox both with the 32 and 64bit architecture didn’t show a discernible difference at all. When you’re using a browser heavy with extensions and/or tabs, it is usually the single process nature that slows you down.

    Yes there are security implications too, but the article only looks at one side of it. Don’t forget that there are also security issues that will only affect the 64bit Firefox, but it’s not unlikely that more of them remain undiscovered while so few people use the browser in that architecture. That’s basically the ‘security through obscurity’ principle, which may make you safer from the 99 harmful intrusions until you find that one unicorn.

    In short, there are as many reasons for as there are against switching Firefox from the 32 to its 64bit architecture. If you’re merely looking at it from a performance point of view, then don’t bother. At all. More often than not, user devices don’t have plenty of RAM to spare.

    1. Jojo said on January 27, 2017 at 11:41 am

      Thanks man, exactly what I feared!
      My FF is already struggling, well, my 4GB RAM’ed PC is…

      Passsss =]

      1. Xan said on January 27, 2017 at 3:25 pm

        Mozilla developers consider that 64-bit has enough advantages that they intend to upgrade even users with 4Gb, once it’s ready. I think they’re right but I will not upgrade until they decide it’s time to upgrade everybody.

        For me, 64-bit is akin to Nightly or Beta, and I’m a Release user at the moment so I’ll stay with 32-bit until 64-bit is deemed ready.

  24. Ann said on January 27, 2017 at 11:18 am

    Martin, why in the hell do you go through the :about screen.
    just use %appdata%\mozilla from command prompt or startmenu and you are there. ctrl+c & V the firefox folder there jsut for backup.

    unless you have somehow changed the default location, which is not everybody can do an those who have done it , know where to find it anyway.

    1. Martin Brinkmann said on January 27, 2017 at 11:52 am

      You need to remember that the guide is for users of all experience levels. While a good part of Ghacks’ audience knows how to use the command prompt, I think it is easier for regular folks to do this from within Firefox.

  25. Anonymous said on January 27, 2017 at 11:16 am

    still no java support in 64bit

    1. Martin Brinkmann said on January 27, 2017 at 11:52 am

      Java won’t be supported by 64-bit Firefox.

  26. indig0F10w said on January 27, 2017 at 10:12 am

    This article is incorrect since this will not upgrade anything, it will install in C:\Program Files and leave old installation in C:\Program Files (x86). You will also have FF x64 and x32 entries under Programs and Features. So, yeah, nice upgrade guide…

    1. Gary D said on January 27, 2017 at 10:56 am

      So you get to choose whether you use 32 or 64 bit :)

    2. agree said on January 27, 2017 at 10:26 am

      agreed, the article is incorrect. I confirmed that I can run both Firefox in one computer, though they still use the same profile.
      there’s no ‘upgrade’ function from mozilla yet.

  27. T J said on January 27, 2017 at 10:06 am

    I have been using Cyberfox 64 bit for nearly a year. Cyberfox can be downloaded in 32 or 64 bit from 8pecxstudios. It supports both Intel and AMD chips. It is very stable, fast and reliable. It can use all the plugins and extensions which are compatible with Firefox.
    I recommend giving Cyberfox a try. The link is below.


    1. CHIMERA said on May 18, 2017 at 8:12 am


      Your probably thinking ………………………………….
      So in short for the next 12 months cyberfox will be on the ESR time line getting security updates at the end of which will likely be the EOL
      (End of life) now that is a long time and factors may change lifestyle wise that will allow the project to continue after the 12 months but at this stage
      its (EOL) at the end of the ESR Cycle.

  28. pd said on January 27, 2017 at 9:40 am

    Mozilla needs to support 64 bit better. They’re a bunch of wierdos these days. No idea what they are doing. They just released yet another “oops, we screwed up another build/release” patch in the form of 51.0.1 … this time they broke geolocation and some e10s/addon compat went wrong.

  29. Me said on January 27, 2017 at 9:08 am

    i have been using the 64-bit version for sometime now and have had now issues with the browser.

  30. J said on January 27, 2017 at 8:53 am

    64-bit here. Stable

  31. max said on January 27, 2017 at 8:21 am

    Using 64-bit Cyberfox for about a year now and i’m content with it. It’s stable, fast and reliable.

    1. Mike J. said on January 27, 2017 at 3:39 pm

      Me, too. Also Waterfox. No complaints with either.

  32. Nik said on January 27, 2017 at 7:42 am

    Is it stable? How has your personal experience been?

    1. Xan said on January 27, 2017 at 2:51 pm

      It’s good, but slightly less stable and slower than 32-bit. This is going to change as more people use the 64-bit browser and Mozilla gets more data and gives more developer attention to bringing up 64 to 32’s level. This is a direct consequence of more people switching to 64-bit.

      But if you have problems with 64-bit, try 32-bit. Speed is still better with 32-bit at the moment, there’s a benchmark about this lying around somewhere.

      1. Kin said on January 27, 2017 at 4:44 pm

        It’s not slower, have no worries. Benchmarks are useless here as you will never perceive the difference in ms that the benchmark does detect.

        Like mentionned also, what you will noticed is that it holds up much better once you reach high usage of memory. The 32 bits version was starting to crawl real bad on my desktop after reaching about 1.5 Gb of memory.

        As for stability, about 300% more stable than the 32 bits version, but this change alot depending on your OS. It crash almost never under windows 10 while it was somewhat unstable under my windows 7 machine.

      2. Yuliya said on January 27, 2017 at 4:19 pm

        I personally haven’t found any performance differefnce between 32 and 64 bit FireFox. The only difference I noticed is that under heavy usage, the 64 bit one performs better. That being said, I have multiptocess disabled.
        Stability-wise they’re both the same. I have encoutered with neither the 64 nor with the 32 bit ones any crashes or rendering issues. I’ve been using the 64 bit version (on Windows 7) since it’s been promoted to the stable channel.

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