Some websites have the ability to store information, such as files, in your local storage, and these files can only be removed manually by you. This helps the website run faster and prevents information from being lost if you lose your connection. Firefox shows you how much space is being used and lets you manage these settings to free up space.

Access site storage settings

You can access site storage settings in your Firefox settings as follows:

1. In the Menu bar at the top of the screen, click Firefox and then select Preferences or Settings, depending on your macOS version.Click the menu button and select Settings.
2. Select the Privacy & Security panel and go to the Cookies and Site Data section.

Delete site storage for individual websites

1. In the Cookies and Site Data section, click Manage Data… . You'll see a list of sites and how much information each site is storing on your computer.

   

2. Click the site you want to remove and click Remove Selected (or click Remove All to remove all stored cookies and site data).
3. Click Save Changes to finish.

For more information about clearing cookies for individual (or all) websites, see Clear cookies and site data in Firefox.

Clear data stored by all sites

1. In the Cookies and Site Data section, click Clear Data….

   

2. Put a check mark next to the type of information you want to clear:
   • Cookies and Site Data (to remove login status and site preferences)
   • Cached Web Content (to remove stored images, scripts and other cached content)
3. Click the Clear button.

For more information on clearing cached web content in Firefox, see How to clear the Firefox cache.

Allow or block websites from storing information

You can set up Firefox to always allow or block specific sites from storing information. You can also allow a site to store only for a single session.

1. In the Cookies and Site Data section, click Manage Exceptions….

   

2. Type in the exact address of the site you want to allow or block, or select the site if it's already on the list.
3. Click Block , Allow for Session or Allow.
4. Click Save Changes to finish.

See these articles for additional information:

• Block websites from storing cookies and site data in Firefox
• Websites say cookies are blocked - Unblock them