One of the World's Most Popular Web Browsers for Mac

Firefox for Mac

Firefox 40.0

  -  73.81 MB  -  Freeware

Sometimes latest versions of the software can cause issues when installed on older devices or devices running an older version of the operating system.

Software makers usually fix these issues but it can take them some time. What you can do in the meantime is to download and install an older version of Firefox 40.0.


For those interested in downloading the most recent release of Firefox for Mac or reading our review, simply click here.


All old versions distributed on our website are completely virus-free and available for download at no cost.


We would love to hear from you

If you have any questions or ideas that you want to share with us - head over to our Contact page and let us know. We value your feedback!

  • Firefox 40.0 Screenshots

    The images below have been resized. Click on them to view the screenshots in full size.

    Firefox 40.0 Screenshot 1
  • Firefox 40.0 Screenshot 2
  • Firefox 40.0 Screenshot 3
  • Firefox 40.0 Screenshot 4
  • Firefox 40.0 Screenshot 5

What's new in this version:

- New: Added protection against unwanted software downloads
- New: Suggested Tiles show sites of interest, based on categories from your recent browsing history
- New: Hello allows adding a link to conversations to provide context on what the conversation will be about
- New: New style for add-on manager based on the in-content preferences style
- New: Improved scrolling, graphics, and video playback performance with off main thread compositing (GNU/Linux only)
- New: Graphic blocklist mechanism improved: Firefox version ranges can be specified, limiting the number of devices blocked
- Changed: Add-on extensions that are not signed by Mozilla will display a warning
- Changed: Smoother animation and scrolling with hardware vsync (Windows only)
- Changed: JPEG images use less memory when scaled and can be painted faster
- Changed: Sub-resources can no longer request HTTP authentication, thus protecting users from inadvertently disclosing login data
- Changed: NPAPI Plug-in performance improved via asynchronous initialization
- HTML5: IndexedDB transactions are now non-durable by default
- HTML5: Implemented AudioBufferSourceNode.detune to modulate playback rate in cents, a logarithmic unit of measure used for musical intervals
- Developer: Improved Performance tools in the developer tools: Waterfall view, Call Tree view and a Flame Chart view
- Developer: Console API messages from SharedWorker and ServiceWorker are now displayed in web console
- Developer: Inspector now searches across all content frames in a page
- Developer: New rules view tooltip in the Inspector to tweak CSS Filter values
- Developer: New page ruler highlighting tool that displays lightweight horizontal and vertical rules on a page
- Fixed: Kannada text does not display properly in built-in pdf viewer

Fixed bugs:
- Bug 1137580 - Do not use system realloc in mozjemalloc-exposed _recalloc.
- Bug 1179262 - Remove PlayPreview usage from PDF viewer.
- Bug 1178058 - Don't convert an expanded principal into inheriting the current principal. Just pretend like the null principal did the load (like LOAD_FLAGS_DISALLOW_INHERIT_OWNER does).