How to Find a Cache File in Mozilla Firefox

by Kevin Lee

As you surf the Web, websites send a variety of files to your Firefox browser. These files may consist of images, text, JavaScript or even MP3 files. Firefox caches these files to speed up your browsing experience. For instance, if you revisit a site that contains a large MP3 file, the browser retrieves that file from your cache instead of downloading it from the website. By learning to explore the Firefox cache, you can view and listen to old files that you previously encountered while surfing the Web.

Locate Cache

Launch Firefox.

Type "about:cache" in the browser's address bar.

Press "Enter." A new Web page opens and displays information about the Firefox cache.

Locate the section named "Disk Cache Device." Click the "List Cache Entries" link. The "Disk Cache Device" page opens and displays blocks of information that describe the files in the cache. Several informational fields appear in each block. The "Expires" field shows when the cache file will expire. The "Data Size" field shows the file's size. The "Key" field contains a URL. This URL identifies the website that placed the file in the cache. For instance, if you see a link with the words "" in it, the cache file came from that website.

View Cached Files

Scroll through the list and note the text that appears at the end of those links. You may see words such as ".jpg,' ".gif" and ".png." These are image files. If you are looking for a cached image that you remember seeing while browsing, it will have a link that contains one of these file extensions.

Locate a link that contains an audio file extension such as ".mp3" or ".wav." These are cached audio files. After hearing a song while browsing, you may be able to find it in the cache.

Search for a link that contains ".css" or ".js." If you are a Web developer, you may find these files useful. They are Cascading Style Sheet and JavaScript files that Firefox has cached.

Click a link that contains an image file extension as described previously. A new page opens. This page also has a link. Click that link. A new page will display that image.

Click Firefox's "Back" button to return to the "Disk Cache Device" page that lists the cached files. Click a link that contains an audio file extension such as ".mp3." A new page containing a link to that file opens. Click that link to listen to the audio.

Click the browser's "Back" button again to return to the "Disk Cache Device" page. Continue to explore the entries on that page and search for files you find interesting.


  • check You can also search the cache using keywords by pressing "Ctrl" and "F." A "Find" box appears at the bottom of Firefox. There you can type keywords such as ".mp3," ".jpg" or even the name of a website. For instance, if you want to find a cached ".css" file, enter ".css" (without the quotes) in the "Find" box and press "Enter." Firefox will locate a cached CSS file.


  • close When you clear your cache using Firefox or a browser cleaning tool, the cache's existing contents disappear. As you surf, new entries will repopulate the cache.

About the Author

After majoring in physics, Kevin Lee began writing professionally in 1989 when, as a software developer, he also created technical articles for the Johnson Space Center. Today this urban Texas cowboy continues to crank out high-quality software as well as non-technical articles covering a multitude of diverse topics ranging from gaming to current affairs.

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