Unfortunately, you probably need to disable McAfee Site Advisor on the Add-ons page. Either: * Ctrl+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons In the left column, click Extensions. Then you can find it on the right side. Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the page and click one of the links as the last step. Success? For reference: * [https://support.mozilla.org/questions/1053195 why do is ee a different language signs on top ogf page] * [https://support.mozilla.org/questions/1052945 the language viewed on my tabs will randomly change from english to something like Korean or something] * [https://support.mozilla.org/en-US/questions/1034427 Firefox tabs display weird characters] * [https://support.mozilla.org/questions/1027393 Active Tab has floating chinese characters as well as the tab name how do I get rid of this?]