Anti-virus vendor Avira was left with egg on its face after blocking rival BitDefender as a Trojan.
A bad virus definition for Norton Anti-Virus left users unable to play World of Warcraft last week.
McAfee has pledged to refund "reasonable expenses" for those caught by its false-positive update.
A bad signature update for McAfee anti-virus software quarantines svchost.exe - killing Windows.
An update to Kaspersky's anti-virus software left many users unable to browse the most innocuous of websites after the company mistakenly added Google's Adsense to its detection.
A trojan application which attempts to steal banking details, uncovered by First Tech Credit Union, has been removed from the Android Market - but leaves unanswered questions.
A Space Invaders clone for the Mac deletes a file each time an enemy is killed - but its author claims it is art, rather than malware.
Security firm Finjan has alerted users to a particularly insidious new Trojan which infects Windows-based systems and steals money from on-line banking systems.
Microsoft has released its Security Essentials, a free anti-virus, anti-spyware, and anti-malware package for Windows - and reviews are positive.
A pair of flaws in Adobe Flash Player and Adobe Reader are being exploited by ne'er-do-wells to drop a Trojan horse onto Windows boxes.
A bug in the latest virus definitions for Computer Associates' range of anti-virus products left customers with important system files missing.
Microsoft's in-house anti-virus, Security Essentials, has hit public beta status - although it's limited to the first 75,000 downloaders at present.
Anti-virus vendors Symantec and McAfee have been find $375,000 each after New York's attorney general found they had mislead customers over subscription renewals.
A bug in a signature update for AVG 7.5 and 8 has caused the anti-virus software to mistakenly classify a critical Windows system file as a Trojan horse.
A mis-implemented feature in the anti-virus package AVG 8, which caused massive amounts of spurious Internet traffic, has been fixed today.