Faulty signature updates on Wednesday resulted in Symantec's anti-virus packages falsely identifying that Yahoo! mail was contaminated by malware.
Symantec published a signature update later on Wednesday that resolved the problem.
Updates to security software signatures can occasionally result in false alarms against legitimate applications, a problem far from confined to Symantec. For example, in November Microsoft's Windows Live OneCare warned that Gmail was infected by malware.
And in February 2006, an update to Microsoft anti-spyware incorrectly labelled two versions of Symantec's anti-virus software as Trojan horse malware. ®