Hi, Please check to see if you are using the Firefox feature "Always use private browsing mode". You can read more about this feature under the heading "Can I set Firefox to always use Private Browsing?" in this article: https://support.mozilla.org/en-US/kb/private-browsing-use-firefox-without-history. If you disable the feature, AdBlock should work again. Please reach out to us at help@getadblock.com if you still need assistance. --AdBlock Support