Is this on your Android device or on a desktop/laptop computer? I'm going to assume Windows for the moment. The usual cause of this kind of problem is a bad add-on. Here's my suggested procedure for tracking down and removing bad add-ons. I know it seems long, but it's not that bad. (1) Open the Windows '''Control Panel''', Uninstall a Program. After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. This can help in smoking out undisclosed bundle items that snuck in with some software you agreed to install. ''Don't be fooled by seemingly innocent or important names if you do not remember choosing to install them.'' Take out as much trash as possible here. ''Note: Windows XP's Add/Remove Programs control panel doesn't have an "Installed on" column but you could try sorting by the recently used/run date.'' (2) Open Firefox's '''Add-ons page''' using either: * Ctrl+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons * in the Windows "Run" dialog, type or paste <br><code>firefox.exe "about:addons"</code> In the left column, click '''Plugins'''. Set nonessential and unrecognized plugins to "Never Activate". In the left column, click '''Extensions'''. Then, if in doubt, disable (or Remove, if possible) unrecognized and unwanted extensions. (Note: you might not be able to manually Disable extensions in Safe Mode because they are disabled automatically.) Often 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? (3) You can search for remaining issues with the '''scanning/cleaning tools''' listed in our support article: [[Troubleshoot Firefox issues caused by malware]]. These on-demand scanners are free and take considerable time to run. If they finish quickly and especially if they require payment, you may have a serious infection. I suggest the specialized forums listed in the article in that case. Success?