“…Several readers reported to heise Security that Norton Antivirus and Internet Security from Symantec both issued a security alert and pushed various files into quarantine after they installed the latest Firefox update which in turn caused Firefox to malfunction….” The update is 3.6.6 28 June 2010 Source: The H Security: News and Features More  http://www.h-online.com/security/news/item/Norton-produces-false-alarm-after-Firefox-update-1030099.html