Firefox Running Slow or Freezing on Mac? (Try These 6 Steps)

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Firefox is one of the most popular web browsers developed by Mozilla, a non-profit organization. The Mozilla team has been upgrading the browser and added many great features, making the browser more powerful, privacy-protected, and easy to use.

However, performance issues with the Firefox browser are constantly reported by users. How many crash reports have you sent to Firefox? I know I’ve sent quite a few!

If you have used FireFox on your MacBook Pro for a while, most likely you have encountered issues like page delays, cursor becoming a running pinwheel, unexpected crashes, etc.

As a Firefox user for years, I have had to force quit the browser many times because it’s simply stopped responding or working.

So, why is Firefox running slow or continuously freezing?

 Firefox Browser
To date, the latest version of Firefox on Mac is 72.0

Firefox Slow on Mac: Possible Causes

Depending on the macOS version your Mac is running, and the Firefox version you use, the reasons may vary. But here are some general causes:

  • You are browsing sites that contain heavy content such as video ads, images, Javascripts, etc. Those elements are very likely to cause Firefox to freeze.
  • You have opened many tabs and windows while browsing, especially those heavy pages.
  • Too many resource-intensive applications are running, leaving Firefox little space to process its requests.
  • You are using a very old version of Firefox.
  • Your Firefox has lots of caches, browsing histories, downloads, and extensions.
  • Your Mac is slow in general, making you feel Firefox is the culprit.

How to Fix a Slow or Freezing Firefox on Mac

Follow the step-by-step fixing guide below, you should be able to resolve most Firefox performance issues on Mac.

Step 1: If Firefox becomes totally unresponsive, force quit.

Firefox becomes totally unresponsive

If it turns out that your Mac is frozen, you’ll probably have to do a hard reboot by pressing the power button – holding it for three seconds, then press it again to restart your Mac.

Step 2: Open Firefox browser and check the version.

Click on the Firefox icon on the menu bar in the top left corner, and you’ll see “About Firefox”. Select it and a window will pop up showing you the current version you are using. If it’s not up to date, update it right away.

About Firefox

Check out this article by Kanika Modi on how to fix “sorry no manipulations with clipboard allowed” issue.

Step 3: Lighten your browser.

You can do so via a few efforts:

  • Clearing cookies and browsing history (Firefox Menu > History > Clean recent history), don’t forget those unused bookmarks as well.
Clearing cookies
  • Removing useless extensions (Firefox Menu > Preferences > Extensions & Themes > Extensions)
Removing useless extensions
  • Disabling unnecessary plugins (Firefox Menu > Preferences > Extensions & Themes > Plugins)
Disabling unnecessary plugins

Step 4: Clean your Mac hard drive.

You can do this manually, or save time by using a Mac cleaner app like CleanMyMac X. It will help tune up your overall Mac performance, as well as make Firefox run more smoothly.

 Clean your Mac hard drive

Step 5: Adjust web browsing habits.

Always try to open one Firefox window, and close tabs/pages you don’t need to read, especially when you finish reading content from big magazine websites like Forbes, Huffington Post, Macworld, etc. which I view as heavy sites because they usually contain video ads.

Meanwhile, avoid multitasking. When you are using Firefox, close as many other apps as possible to squeeze more system resources (CPU, RAM) for Firefox.

Step 6: Switch to an alternative web browser.

Sometimes Firefox just doesn’t work well with certain versions of macOS, for example the previous macOS Big Sur. Many Mac users have observed the performance issue. See here or here for yourself.

If Firefox is still running slow or freezing randomly, use an alternative browser like Google Chrome or Apple Safari though they sometimes act up too.

Check this article to know more about Force Quitting on Mac.

Anyway, hope these steps have helped you speed up Firefox a little bit. If you have any further questions, let us know by leaving a comment below.

About Lorena
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Lorena holds a 13-inch Touch Bar MacBook Pro with Apple M1 Chip. Her role involves editorial management from writing to editing and ensuring that the articles are informative, useful, and relevant to readers who are new to Mac.

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  • ALH

    I just switched to Google Chrome and the problem vanished. While using Firefox, I was having issues with all sorts of applications running on my macbook pro. I do have an older macboo, but it works fine and now that I’m no longer using Firefox, I’m probably going to hold onto it longer than I was planning to. Sorry Mozilla, but your browser is just to high-maintenance.

  • Maurice Lewis Fishman

    Support I have been a user of Firefox for many years on my MacBook Pro and on ipad.
    I have a high speed internet provider and get good results using a test called Brebandskollen, but get a much slower result with firefox.Can you advise me what I can do to improve the speed.

    Thank you from a
    82 year old user.

  • Joe Best

    Same here. Imleaving firefox its just too slow compared to safari and chrome

  • Jon

    My Mac Firefox has been freezing regularly and I’ve tried every suggestion I could find on the Web. Today I saw a suggestion that I hadn’t tried before. Uncheck “use hardware acceleration” in the Preferences/General pane. I now actually think that has solved it. I’ve seen false dawns before, but this looks very promising.

    • macbookproslow logo


      Interesting. Thanks for sharing this, Jon!

    • Craig

      Brilliant! Works for me too!

  • Fritz

    nothing I’ve tried has fixed issues with FFx. I’m on Mavs on a ’13 MBA. Perhaps Mavs is the issue.
    But the latest versions of both Chrome and Safari don’t have any issues other than that they are slower than FFx.
    FFx screams compared to either, but after 15 mins or so the fans crank to 5500 and the CPU is chocked.

  • Larry

    I’m finally going to give up on FireFox (after many years)…I just got the spinning wheel there.
    I get the spinning wheel every 20 seconds, and FaceBook is painful sometimes.
    Going to Chrome, I think.

    • macbookproslow logo


      It’s definitely an option. I now use Google Chrome most of the time, sometimes I check out Apple Safari as well 🙂

  • Lori

    Yeah, Nothing but pinwheels when I click ANYTHING on Firefox on my brand new MacBook Pro w/Touch Bar on Sierra. Will try some of these and see if anything helps. Thanks for this!

  • jools

    Tried some of your tips above but it’s still running slow & pages are taking ages to load. Now in the position where I’ve lost stuff that I would have preferred to keep with the added frustration that it’s made no difference! Even typing this message is taking much longer than it should because type takes a long time to appear.

    Thanks admin – feel you are trying to help but I can’t keep wasting time trying to solve this so will have to move to another browser.


    • macbookproslow logo


      Yep, sometimes switching to another browser is the best solution. To be frank, nowadays I use Chrome most of the time 🙂 Thanks for your comment and feedback anyway.

  • jools

    Thanks for the tips which I will try. So far have tried resetting firefox, clearing cache, switching off adblock & even switching router channels but nothing has helped. The help pages are confusing & despite numerous attempts haven’t been able to contact anyone in firefox community for help. It’s extremely frustrating & unacceptable. If firefox can’t sort these problems out, it needs to close.

    One big question – why does this keep happening every few months? Getting to the point where I want to switch servers. Can anyone recommend a reliable server?

  • Rameez

    I think the culprit is El Captain, because I am facing this issue since I upgraded to El Captain before that it was running like a charm, I always have dozens of tabs open due to my work requirement but I never experience that on any Mac or PC in past.

    I am going to run Macbooster and delete some extensions (that I can run on chrome).

    thanks admin for telling all possible ways 🙂

    • macbookproslow logo


      Good to know and you’re very welcome!

  • Klaus

    After upgrading my MacBook Pro to macOS Sierra 10.12.2, even after re-installing Firefox 50.1.0, Firefox will at first be quick but then slow down to nothing. I cannot even quit Firefox at that point but have to force-quit it. Very annoying. I have tried everything.

    • Pierre Thibault

      Same problem here. At first Firefox is running fast then it starts getter slower and slower. It seems to be crashing the Mac but Mac OS should be stronger than that.

      I am very tired at the poor quality of Sierra and the Mac experience. I am thinking about getting rid of my Mac and go for Windows.

  • marion

    this is good info and to the point thank you