Clearing the cache from Firefox 21 is often necessary to solve certain web page and browser problems that sometimes occur.
The cache in Firefox 21 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 from the Internet.
Clearing the cache in Firefox 21 is completely safe and should not remove any important data from your computer.
Follow the easy to follow steps below to clear the cache from your Firefox 21 browser:
Open Mozilla Firefox 21.
Click the Firefox button and then choose Options.
Note: If you're using the menu bar, choose Tools and then Clear Recent History and then skip to Step 5 below.
With the Options window now open, click the Privacy tab.
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.
In the Clear Recent History window that appears, set the Time range to clear: to Everything.
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 with the cache in the next step.
Tip: Don't see anything to check? Click the button next to Details.
Click on the Clear Now button.
When the Clear Recent History window disappears, all of the files saved (cached) from your Internet browsing activities in Firefox will have been removed.
Older versions of Firefox, particularly Firefox 4 through Firefox 20, have nearly identical processes for clearing the cache but please try to keep the latest version of Firefox installed if possible.