A false positive is identifying a file as a virus when it is not a virus. If an antivirus program is configured to immediately delete or quarantine infected files, false positives in essential files can render the operating system or some applications unusable.
In May 2007, a faulty virus signature issued by Symantec mistakenly removed essential operating system files, leaving thousands of PCs unable to boot. Also in May 2007 the executable file required by Pegasus Mail was falsely detected by Norton AntiVirus as being a Trojan and it was automatically removed, preventing Pegasus Mail from running.
Norton anti-virus has falsely identified three releases of Pegasus Mail as malware; Norton anti-virus can delete the Pegasus Mail installer file when this happens. Spotify has been flagged as a false positive by Symantec and McAfee products. Even when the false positive is rectified by an update, users may have to re-install Spotify.
