Websites you visit store cookies and other site data on your computer. The stored data contains information such as site preferences and login status. This article describes how to block websites from storing this data in Firefox.

• See Where are my logins stored? to learn more about website logins.

Block cookies or persistent storage for a single website

You can use the Page Info window to set Firefox to block cookies or stored data from one website:

1. Go to the website you wish to block from setting cookies or storing site data in Firefox.
2. If the Menu bar is enabled,In the Menu bar, click Tools and select Page Info from the drop-down menu.
   Alternatively, click the padlock to the left of the web page address, click the right arrow > in the Site Information drop-down panel and then click the More Information button in the next panel.
3. In the Page Info window, select the Permissions panel.
4. Underneath Set Cookies or underneath Store Data in Persistent Storage, remove the check mark from Use Default.
5. Change the setting to Block.

   

6. Close the Page Info window.

You will need to remove any cookies or site data that the website has already set in Firefox. For instructions, see Clear cookies and site data in Firefox.

Block cookies and site data for more than one website

If you have more than one website you want to block, using the Page Info window for each site can be time-consuming. You can block individual websites from setting cookies and storing site data, 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.

   

3. Click Manage Exceptions…. The Exceptions - Cookies and Site Data dialog box will open.

   

4. Type in the exact address of the site you want to block.
5. Click Block.
6. Click Save Changes to finish.

To remove cookies that were stored previously, see Clear cookies and site data in Firefox.

Viewing a list of blocked sites

To see a list of sites that you have blocked from setting cookies and storing site data:

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.
3. Click Manage Exceptions…

The Exceptions - Cookies and Site Data dialog box that opens will show you which sites you have blocked from storing cookies.

Block cookies for all sites

To set Firefox to block cookies from all websites:

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.
3. In the Enhanced Tracking Protection section, select Custom and check mark Cookies.

   

4. Use the drop-down menu to choose the type of cookies to block. Warning! Some sites will not work properly with all cookies blocked.
5. Close the Settings page. Any changes you've made will automatically be saved.

Related articles

• Websites say cookies are blocked - Unblock them
• Third-party cookies and Firefox tracking protection
• Clear cookies and site data in Firefox