Mozilla: no more Windows 64-bit builds of Firefox

Martin Brinkmann
Nov 22, 2012
Updated • Nov 22, 2012
Firefox, Windows software

Where is the 64-bit version of the Firefox web browser for the Windows operating system? That's a question that I have been asking myself for the past couple of years, probably ever since I updated to a 64-bit version of Windows 7 Professional. Mozilla is offering 64-bit versions of the browser for Mac and Linux, but Windows, the operating system that is used by the majority of Internet users? There have been nightly and custom builds of 64-bit versions of Firefox, but that is about it.

64-bit versions have been in development for quite some time, a roadmap released in 2011 for instance lists the Windows 64-bit version of Firefox under Firefox 5. That did not happen but still, most Firefox users probably expected that Mozilla would eventually release Firefox 64-bit for Windows.

That dream may have been shattered now with the announcement that Mozilla decided to stop producing 64-bit builds for the Windows operating system.

Per newsgroup discussion. Please stop building windows 64 builds and tests. This includes the following subtasks, which I'm not filing specific bugs on but you may want to break these out:

* stop building win64 nightlies
* repatriate existing win64 nightly users onto win32 builds using a custom update
* stop doing win64 "hourly" builds on mozilla-central and other branches
* disable the win64 option in try/trychooser

This bug is not the place to argue about this decision, which has already been made. If there is critical data which you think should be heard about this decision, please post it to

What are the reasons given?

  • Many plugins are not available in 64-bit versions
  • The plugins that are available do not work correctly in Firefox
  • 64-bit versions are slower than 32-bit versions of Firefox
  • 64-bit users can't test all features of the browser (in regards to Nightly)
  • 64-bit crash reports are not high priority
  • User frustration because of this
  • Stability team frustration because crash stats do not distinguish between 32-bit and 64-bit builds.

firefox 64-bit version

About 50% of Nightly users are currently working with a 64-bit version of Firefox. Since there won't be any updates for the versions they are running, they somehow need to receive information about the change.

Mozilla plans to offer an update for those users to "convert" their 64-bit version of Firefox Nightly to a 32-bit version. It is not clear when this is going to happen though but it will happen at around the time the Nightly builds are no longer produced and uploaded to the servers. It is not clear if third party builds of Firefox, for instance the 64-bit Waterfox browser, are affected by the change as well.

This does not mean that there won't be a 64-bit version of Firefox ever, but for the foreseeable future, it is not going to happen.

The only (major) browser makers offering 64-bit browsers right now are Microsoft and Opera. Everyone else is only offering 32-bit versions for Windows.

Some Firefox users will certainly be disappointed by the move even if it does not impact them right away. I for one dislike Mozilla's current trend to move away from development of certain programs, Thunderbird and now 64-bit Windows builds come to mind. It gives the impression that these products are not worth the company's time, and as a result, that users who like those products are not Mozilla's top priority either anymore. (via Sören)


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  1. Jeffery Marizo said on December 21, 2012 at 7:51 pm

    FF is looking at MONEY facebook means more than 64 bit any day plus that fact bunch of lazy as***.

  2. brendan said on December 3, 2012 at 7:56 am

    for what it’s worth, if the 64bit FF goes away, I’ll simply stop using FF, and there’ll be one more person using competing browsers. the 64bit builds of waterfox made me very happy. this news makes me very sad.

  3. jarfil said on November 27, 2012 at 1:29 pm

    Windows 64-bit support was the only reason I used FF Nightly… so from now on Mozilla will hear no more bug reports from me, no low-level, no nothing.

  4. blaaaaaat said on November 25, 2012 at 12:17 am

    Sorry, but I’ve gotta call shenanigans on the reasons for discontinuing X64 buils for win64 given by mozilla (are you reading along Benjamin Smedberg ?), and I’ll explain why by countering one after one.

    – Many plugins are not available in 64-bit versions
    # In fact, they are. Mozilla is lagging behind on this one.

    – The plugins that are available do not work correctly in Firefox
    # Another big heap of BS!! I’ve been viewing youtube in FF nightly win64 builds happily for quite some time now.

    – 64-bit versions are slower than 32-bit versions of Firefox
    # If Mozilla took the time to optimize for AMD64, FF would definitely run faster, if only it were for the extra general purpose registers available. And since FF is still a 1-process web browser, compiling for AMD64 would also remove the 2GB per process barrier and eliminatie the annoying “2-5 sec UI freeze every 1 min” when one’s getting close to that limit.

    -64-bit users cant test all features of the browser (in regards to Nightly)
    # That depends on whether you choose to expose all available functionality in the build in question or not, so non-sequitor.

    – 64-bit crash reports are not high priority. User frustration because of this.
    # It has been a stupid move to relegate 64bits crash reports to low/no priority status, since crashes on the AMD64 build can reveal bugs in the code that don’t expose themselves in the x86 branch.

    -Stability team frustration because crash stats do not distinguish between 32-bit and 64-bit builds.
    # That’s something you’ve done to yourself Mozilla. You could have easily modified the crash logger&reporter to send CPU arch along with OS and Build and save yourself the hassle of doing the distinguishing manually.

    Sorry, but this is an ill-conceived decision made for all the wrong reasons. I do understand that Mozilla apparently doesn’t have the resources to sufficiently maintain all 4 channels on both the x68 and AMD64 arch. But that could be mitigated by quitting the aurora branch, since that’s only a glorified Nightly branch, on both archs and only offer ESR and Nightly builds for AMD64. Cos really, Nightly WIn64 isn’t that unstable at all, speaking from several years of browsing experience.

  5. A&L said on November 23, 2012 at 7:36 pm

    I use waterfox and it works great, can’t get firefox to work right, it keeps minimizing the window when i click on a link
    tried completely removing with revo, reinstall and same thing, tried safe mode and tried new profile and same thing, pain in the @ss when i have to keep going to the task bar to maximize the window after clicking a link, it opens but goes immediately to the task bar
    happens on both my laptop and desktop win7 64
    i will switch to opera before going back to FF 32

  6. Miguel Angel Fuentes Aranda said on November 23, 2012 at 12:47 am

    Unfortunatelly I cannot use Waterfox or Pale Moon because they have a strange bug: if I open and close bookmarks drop-down menu, it leaves small parts of it near the task bar (doesn’t redraw this space correctly and doesn’t erase itself after closing). Only Firefox Nightly comes without this bug. Now I have the last working build from 19.11.2012 and I will use it in future. I cannot take IE or Opera because of add-ons AdBlock Plus and Miltifox 2.

    1. David said on November 23, 2012 at 5:07 pm

      I have been using Pale Moon for several months without problems. Maybe you need to update your graphics driver.

      I have been using Pale Moon with AdBlock Plus, Better URL Bar, BetterPrivacy, DoNotTrackPlus, NoScript, and Tab Mix Plus.

  7. Midnight said on November 22, 2012 at 8:48 pm

    You guys might want to read this before hitting the Panic button, then switching to another (inferior) Browser!

    No, Mozilla did not just kill Firefox x64 for Windows!

    Firefox x64 isn’t dead, it’s just going to disappear from the nightlies at some point in the near future. It will be back some time later in 2013, but in the meantime Windows users should know that there’s an alternative which doesn’t require leaving Mozilla in the lurch.

  8. Redbad said on November 22, 2012 at 8:43 pm

    I’ve been running Pale Moon x64 for over a year on two Win7 systems without problems and with 15 extensions and 64 bit Flash and Java. Stability and speed have always been impressive. The claim that this browser has been optimized for Windows and “modern processors” is 100% valid in my experience.

    The latest Pale Moon x64 is 15.3 and is the first to have been compiled with Visual Studio 2012 and delivers a striking improvement over the previous versions.

    There is a portable version for those first wanting a try-it-and-see process.

    palemoon dot org for more info.

    1. who said on November 23, 2012 at 8:18 pm

      advertise somewhere else, it sucks more than original

  9. kiiutu said on November 22, 2012 at 8:39 pm

    Ummm, they do realise 64 bit is the future right? Man Firefox really seems to have gone off the rails lately.

    Basically they’re saying ‘It’s toooooo hard, we give up..wahhh’. Pathetic.

  10. Claude LaFrenière said on November 22, 2012 at 8:07 pm

    Another stupid decision from Mozilla.

    I’m using Waterfox a 64b of ff and it works well.

    Now the so-called “reasons”:

    “Many plugins are not available in 64-bit versions”
    Most of plugins are useless such as Java (may be the worst of them).
    I’m using 2 plugins: Shockwave and Silverlight. That’s enough.

    “The plugins that are available do not work correctly in Firefox”
    May be but not the two mentioned before. Which one btw?

    “64-bit versions are slower than 32-bit versions of Firefox”
    Where is the Mozilla test for this. Did they compare Ff 32 b with Waterfox 64b or with their buggy FF 64b?

    “64-bit users can’t test all features of the browser (in regards to Nightly)”
    Which users? How many? Did they really care about users btw?

    “64-bit crash reports are not high priority”
    What an excuse!

    “User frustration because of this”
    Name them!

    “Stability team frustration because crash stats do not distinguish between 32-bit and 64-bit builds.”
    Crash stats is buggy. Must be fixed but Mozilla’s guys are too lazzy to do it

    Somebodies at Mozilla needs a good kick somewhere…

    1. Midnight said on November 22, 2012 at 8:50 pm

      Great excuses from Mozilla, huh?

      Yea, they do need a swift kick in the butt, along with a major wake up call!

      The future IS 64 bit!

  11. Karl Gephart said on November 22, 2012 at 7:28 pm

    I completely agree with Martin’s assessment of 64-bit Firefox and Thunderbird’s discontinuation. Mozilla’s been on a downhill-spiral for quite a while now. If I ever leave ff, it will be to go to Opera, as I continue hearing about innovations over there. They have many years of experience and seem to continue to set the browser industry standards for features. I tried Waterfox for a while and, while working faster at first, it eventually ran slower and made Win7 OS run slower, too. (Yes, I have years of exp performing browser and OS maintenance). Keep in mind that if developers of add-ons are unable to effectively code for 64-bit, the lure of any browser will diminish.

    1. Midnight said on November 22, 2012 at 8:53 pm

      FYI, Thunderbird has not been discontinued!
      It’s still in development with TB 17 just being released and I get “daily” updates, (20.0a1) along with Lightning and the Add-ons!

      Not the least bit concerned about Firefox 64 being dumped, as posted below! :)

  12. Eli said on November 22, 2012 at 5:11 pm

    Many people are under the illusion that 64bit can bring performance improvements over 32bit, it’s a completely false scenario. The most 64bit can bring is more memory space, but considering Firefox’s memory usage, we don’t “really” need more than 2gb of ram.

    1. Midnight said on November 22, 2012 at 8:58 pm

      FYI, 64 bit DOES bring performance improvements over 32 bit, considering that one needs to have more memory and the more memory, the better!

      This may not apply to a Browser, so much, but any 32 bit programs running on a 64 bit system will lag behind the 64 bit!

      Try it for yourself and see!

      There’s a reason why most (better) mother board manufacturers allocate up to 32 GB RAM and No, they’re not in bed with Kingston, Corsair or other memory manufacturers!

  13. lainiwaku said on November 22, 2012 at 2:27 pm

    Mozilla refuse to had h264 to firefox
    now they stop 64bit development . . . i was a 100% user of firefox, but i wonder if i will not go to chrome . . .

    1. Midnight said on November 22, 2012 at 9:00 pm

      Read below and be convinced that Mozilla is only temporarily putting Firefox 64 bit on hold!

      No need to panic or switch, just yet! :)

    2. Pierre said on November 22, 2012 at 4:01 pm


      Chrome neither develops a 64 bits windows version

      H264, it is logical : it is not a free software but a proprietary one

      I am really sorry about this news

      1. ilev said on November 22, 2012 at 7:16 pm

        Chrome develops 64 bit version which is in dev stage

  14. Ibberman said on November 22, 2012 at 12:23 pm

    This might be the death of Pale Moon & Waterfox if all plugin-developers drop support for x64.
    Hopefully it won’t!

    (By the way Waterfox don´t contain AVG Search anymore)

  15. Richard Steven Hack said on November 22, 2012 at 10:31 am

    The reasons listed are just excuses for an apparent inability to produce decent 64-bit code.

    Whether the reason is some difficulty in producing 64-bit code for Windows due to the Windows platform (since they do it for Mac and Linux – where presumably they get a lot of help from the pro programmers for those platforms) or whether Mozilla “just can’t hack it”, it’s still pretty pathetic.

    Clearly the industry has problems finding people who can code 64-bit.

    With every non-XP machine being 64-bit these days (and the processors have been 64-bit since the Stone Age…) it’s ridiculous that there isn’t more 64-bit programs. I think this clearly shows how pathetic the entire software industry is at producing engineered software.

    1. Taomyn said on November 22, 2012 at 11:29 am

      I concur – on Windows Server 2012 you can actually disable 32bit support and I often use Firefox/Waterfox in preference to the locked-down IE that is enabled on the server platform.

  16. ilev said on November 22, 2012 at 10:15 am

    As long as Microsoft isn’t committed to 64 bit OS (Surface RT, recommendations
    not to use Office 64 bit…) why should browsers like Firefox, Chrome.. build 64 bit
    versions ?

  17. Nerdebeu said on November 22, 2012 at 9:58 am

    It seems that Firefox prefers to focus on the integration of Facebook … What a comedown!

  18. browngeek said on November 22, 2012 at 9:39 am

    What about using an alternative Mozilla based 64 bit browser like Pale Moon or Waterfox?

    I’ve tried both and use Pale Moon 32-bit at work (because we are still on XP) and Pale Moon 64-bit at home.

    I used to use Waterfox at home, until they made you install their AVG tool bar (which they have not stopped).

    1. nick said on November 23, 2012 at 8:15 pm

      get source and compile yourself

      personally i trust mozilla more than some guy who “recompile” stuff to advertize himself

    2. Midnight said on November 22, 2012 at 9:01 pm

      Why use a Clone when the real deal is all that you need?

    3. Taomyn said on November 22, 2012 at 11:24 am

      BTW The AVG toolbar, which wasn’t really a toolbar, was removed from Waterfox with v16 and won’t be coming back.

      1. browngeek said on November 22, 2012 at 11:26 am

        Woops, typo in my OP, I should have said the AVG thing has “now” been stopped, rather than “not”.

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