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. foolishgrunt said on May 12, 2020 at 6:45 pm

    I recently played through Chrono Trigger (a few times) on DraStic myself, and I know exactly what parts you’re referring to. :)

    Also, for extra credit.

    DraStic’s .dsv files are essentially raw .sav files, but with a few bytes of DeSmuME-specific data appended to the end (specifically so that this procedure outlined by Ashwin will work). On the other hand MelonDS (my preferred DS emulator on PC) cannot interpret this DeSmuME-specific data, and will need to be stripped out by a hex editor. In this case, you need to use a hex editor to strip it out. Open the file, find this at the very end:

    |<–Snip above h
    ere to create a
    raw sav by exclu
    ding this DeSmuM
    E savedata foote
    UME SAVE-|

    …remove it, and save. Now you have a save file that you can import into any DS emulator that supports raw .sav files (presumably DeSmuME as well, though I have not tried).

    1. Ashwin said on May 14, 2020 at 5:09 am

      Thanks for that.

      MelonDS is pretty good too. There is a new QT version in the works.

      1. fakewooder said on July 26, 2021 at 8:19 pm

        This worked from DraStic to MelonDS Android as well!

        DraStic seems smoother for the time being, but it’s nice to know you can transfer anytime.

  2. Trey said on May 12, 2020 at 9:00 pm

    Nice tip foolishgrunt.

    Off topic but does anyone know the best way to play the original Majora’s Mask on Win10? Best emulator for it I guess?

    1. Ashwin said on May 14, 2020 at 5:27 am

      Project64 Pretty straightforward to use. Enable the N64 plugin.

      You could try Mupen64, it’s good too.

      There are some pretty good texture packs that you can install to make the graphics look better.

      Just FYI, the 3DS remake which has some QoL improvements, runs flawlessly on Citra.

      1. Trey said on May 15, 2020 at 7:19 pm

        Thanks Ashwin

  3. Mageia said on July 12, 2020 at 8:18 pm

    I don’t have those options ‘Import Backup Memory”

    I have desmume 0.9.11 x64 on Linux

  4. delt said on September 10, 2020 at 7:46 am

    Thanks for the info. I was playing a game called “Last window: secret of Cape West” (which wasn’t released where i live) and at one point there’s a puzzle that makes a rather weird usage of the DS’s hardware sensors, which i needed to test on a real DS.

    To convert a Drastic save file into a usable save file for the DSTwo cartridge, you just need to shave off the extra bytes with a command like:

    dd bs=1024 count=256 if=”input.dsv” of=”output.sav”

    …for a 256Kb save file. This should work on any Unix system, ie. Linux (including Android itself) BSD, MacOS etc. For winblows, well….

    Haven’t (yet) tested the reverse operation, but i’d presume if simply copying the file saved on the DSTwo back to the Drastic dir on my phone doesn’t work, i’d just need to re-append the extra few bytes at the end.

  5. Wouter said on February 3, 2021 at 9:22 am

    Transferring the file from Desmume to Drastic doesn’t seem to work for me. I have a DSV and a NDS file with the same name in the backup folder from Drastic on my phone. But when I boot up the game in Drastic it just starts a new game. Anyone an idea what I could be doing wrong?

    1. guille said on March 8, 2021 at 1:40 pm

      Try changing the save file to .dsv instead of .sav, worked for me.

  6. Anonymous said on February 14, 2022 at 4:18 pm

    ok i try the drastic to desmume method with pokemon mystery dungeon explolers of sky and it doesnt work for me for some reason i just get new game option X_X

    1. Jesus Christ said on April 9, 2022 at 11:10 pm


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