Check Point's personal firewall software falsely identified a component of Yahoo! Messenger as a Trojan this week.

ZoneAlarm Pro mistakenly pegged an audio conferencing ActiveX control within Yahoo Messenger as the Yspy Trojan. As a result users of the software were prompted to delete yacscom.dll, a critical component of the IM client. By default the harmless control is placed in quarantine.

Versions of the control in Yahoo version 8.1 trip the false alarm, Beta News (which came across the problem on its own systems) reports.

The issue created an ongoing discussion thread on the ZoneAlarm Support forum. Late on Thursday one user posted a reply from a Check Point rep confirming the false alarm.

Check Point is reportedly working on a fix. The Israeli firm is yet to respond to our own queries on the matter.

False alarms by security software happen periodically to vendors across the industry even though the issue is rarely discussed more widely. Previous examples have included Kaspersky's designation of software as infected by a low-risk virus and Microsoft's Live OneCare anti-virus service falsely warning that Gmail's website was contaminated by a computer virus. ®