ABP 3.0.- latest. FF latest. Win10. Constant error. Also being forced into Outlook.com to address the error, while on another website. This error replaced the constant - a webpage is slowing down your browser. I remedied that w/a a different *about:* - but I do not remember what I inserted. I tried disabling possibly troublesome addons. No help. I let the script run longer using about:config. No help. I am in safe mode, but no error now - which does not mean anything. In prior error (webpage slowing browser), safe mode did not alleviate the problem at all. Cannot view FF or addons, which is why I did not put versions in. Andrew deleted my post. Thank you. Some errors: A script from the extension “Adblock Plus - free ad blocker” is running on this page, and making Firefox unresponsive. It may be busy, or it may have stopped responding permanently. You can stop the script now, or you can continue to see if it will complete. Script: moz-extension://a62ee157-7dfb-…148ca9499be/include.preload.js:12050272Script: https://pro.fontawesome.com/releases/v5.4.2/js/all.js:192376832 Script: https://pro.fontawesome.com/releases/v5.4.2/js/all.js:186986496 Script: moz-extension://a62ee157-7dfb-…148ca9499be/include.preload.js:190863384 Annoying as hell. Thank you.