I think you are right to be suspicious. Firefox does not notify you of updates for add-ons in a pop-up. Instead, you can use these features of the Add-ons page (Command+Shift+a) to check for updates: * In the left column, click Plugins. Then look for a link above the list to "Check to see if your plugins are up-to-date". This leads you to https://www.mozilla.org/plugincheck/ which also does not use pop-ups. * In the left column, click Extensions. Then look for the "gear" button above the list to "Check for Updates". Again, no pop-ups. Since false update warnings may come from websites ''or'' from bad add-ons, while you are on that Extensions list, take a hard look and disable ALL nonessential or unrecognized extensions. Usually a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step. Any improvement?