How To Clear the Cache in Firefox

Instructions on Deleting the Temporary Files Stored by Firefox

A screenshot of the Clear All History Dialog Box in Firefox
Clear All History Dialog Box.

Clearing the cache in Firefox isn't something you have to do every day, but it is sometimes helpful to do so to solve or help prevent certain problems.

The Firefox cache contains locally saved copies of recent web pages you've visited. This is done so that the next time you visit the page, Firefox can load it from your saved copy, which will be much faster than loading it all over again from the internet.

On the other hand, if the cache doesn't update when Firefox sees a change on the website, or the cached files that do load are corrupted, it can cause web pages to look and act strangely.

Follow the easy to follow steps below to clear the cache from your Firefox browser, valid back through Firefox 39. It's an easy process that takes less than a minute to complete.

How To Clear the Firefox Cache

Note: Clearing the cache in Firefox is completely safe and should not remove any important data from your computer.

  1. Open Mozilla Firefox.

  2. Click the Menu button (aka the "hamburger button" - the one with three horizontal lines) and then choose Options.

    If Options is not listed in the menu, click Customize and drag Options from the list of Additional Tools and Features over to the Menu. ​

    Note: If you're using the menu bar, choose Tools and then Options instead. You can also enter about:preferences in a new tab or window.​

    Firefox for Mac: On a Mac, choose Preferences from the Firefox menu and then continue as instructed below.

  1. With the Options window now open, click the Privacy tab on the left.

  2. In the History area, click the clear your recent history link.

    Tip: If you don't see that link, change the Firefox will: option to Remember history. You can change it back to your custom setting when you're done.

  3. In the Clear Recent History window that appears, set the Time range to clear: to Everything.

  1. In the list at the bottom of the window, uncheck everything except for Cache.​

    Note: If you wish to clear other kinds of stored data, feel free to check the appropriate boxes. They will be cleared along with the cache in the next step.​

    Tip: Don't see anything to check? Click the arrow next to Details.

  2. Click on the Clear Now button.

  3. When the Clear Recent History window disappears, all of the files saved (cached) from your internet browsing activities in Firefox will have been removed.

    Note: If your internet cache is large, Firefox may hang while it finishes removing the files. Just be patient - it will eventually finish the job.

Tips & More Information on Clearing the Cache

  1. Older versions of Firefox, particularly Firefox 4 through Firefox 38, have very similar processes for clearing the cache but please try to keep Firefox updated to the latest version if you can.

  2. Looking for more information about Firefox in general? Lifewire has a dedicated Internet Browser section that you might find really helpful.

  3. Using the Ctrl+Shift+Delete combination on your keyboard will immediately put you at Step 5 above.

  4. Clearing the cache in the Firefox mobile app is very similar to when using the desktop version. Just open the Settings menu within the Firefox app to find an option called Clear Private Data. Once there, you can choose what type of data to erase (like the cache or cookies), much like in the desktop version.