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 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.

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.

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.

• Removing useless extensions (Firefox Menu > Preferences > Extensions & Themes > Extensions)

• Disabling unnecessary plugins (Firefox Menu > Preferences > Extensions & Themes > 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.

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.

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.