Hello, Definitely a fake message. Does it pop up only for certain sites? Consider using an adblocker such as [https://addons.mozilla.org/en-US/firefox/addon/adblock-plus/ Adblock Plus] if this is the case. If it pops up regularly no matter which site you are on, it may be a result of malware installed on your computer that you may not be aware of. Check your add-ons for any suspicious extensions: * Tools (or [[Image: New Fx Menu]]) > Add-ons > Extensions Check your list of install programs in Windows - Control Panel > Programs and Features. Usually malware comes bundled with other applications, so if you sort by date and see several applications installed at the same day, it may be easier to find suspicious applications that way. You can also try the Reset Firefox feature which can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information. Note: After resetting Firefox, you will lose any extensions, toolbar customizations, and some preferences. See the [[Reset Firefox - easily fix most problems]] article for more information. --------------------------- You can try these free programs to scan for malware, which work with your existing antivirus software: * [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware] * [http://general-changelog-team.fr/en/downloads/viewdownload/20-outils-de-xplode/2-adwcleaner AdwCleaner] (for more info, see this [http://www.bleepingcomputer.com/download/adwcleaner/ alternate AdwCleaner download page]) * [http://www.microsoft.com/security/scanner/default.aspx Microsoft Safety Scanner] * [http://support.kaspersky.com/viruses/disinfection/5350 Anti-Rootkit Utility - TDSSKiller] * [http://www.surfright.nl/en/hitmanpro/ Hitman Pro] * [http://www.eset.com/us/online-scanner/ ESET Online Scanner] Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article.