Mozilla quietly kills Firefox 64-bit for Windows, despite an estimated 50% of testers using it

Mozilla quietly kills Firefox 64-bit for Windows, despite an estimated 50% of testers using it

Mozilla Engineering Manager Benjamin Smedberg last Friday quietly posted a thread over on the Google Groups discussion board titled “Turning off win64 builds.” By Wednesday, Smedberg had declared that the 64-bit version of Firefox for Windows would never see the light of day, unless Mozilla decides to revert the decision at some point in the future.

Mozilla’s manager listed the following reasons as to why the nightly builds should get the axe:

  • Many plugins are not available in 64-bit versions.
  • The plugins that are available don’t work correctly in Firefox because we haven’t implemented things like windowproc hooking, which means that hangs are more common.
  • Crashes submitted by 64-bit users are currently not high priority because we are working on other things.
  • This is frustrating for users because they feel (and are!) second-class.
  • It is also frustrating for stability team triage because crash-stats does not easily distinguish between 32-bit and 64-bit builds in the topcrash lists and other reports. We basically ignore a set of nightly “topcrashes” because they are 64-bit only. (See bug 811051).

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Some were for it, but most were against the discontinuation. Yet Smedberg had clearly already made up his mind, as he finally declared:

Thank you to everyone who participated in this thread. Given the existing information, I have decided to proceed with disabling windows 64-bit nightly and hourly builds. Please let us consider this discussion closed unless there is critical new information which needs to be presented.

He then went and posted this note over on Bugzilla:

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

Despite his plea, a discussion began anyway. When someone asked how many of Mozilla’s testers are on the nightly 64-bit builds, a Mozilla developer replied “Last I heard, it’s 50% of our nightly testers.”

While the percentage is likely so high since a 64-bit version of Firefox for Windows has never been released, Mozilla is still making a troubling decision here. The company may end up alienating a good chunk of its enthusiasts, or at least those that haven’t yet fled to Google’s Chrome.

Indeed, the decision has resulted in a huge uproar from 64-bit for Windows users, as noted on a Hacker News thread pointing to another discussion board. A few users have even shown off screenshots of Firefox using huge amounts of memory, specifically more than Windows 32-bit can address.

Firefox users are thus left without much of an option. They can switch to OS X or Linux, both of which have full versions of Firefox 64-bit. Windows 64-bit users meanwhile can only consider Internet Explorer and Opera, since both Chrome and Safari don’t offer 64-bit flavors.

We have contacted Mozilla for more information. We will update this article if and when we hear back.

See also: Happy 8th birthday, Firefox! A Q&A with Mozilla chairwoman Mitchell Baker [Video]

Image credit: abcdz2000

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