Microsoft flags Gmail as a virus

From late last week until Sunday night, the Windows Live OneCare security software incorrectly flagged the Google e-mail service as a threat. A warning popped up when OneCare users opened the Gmail Web site, telling them that their systems were infected with a virus called "BAT/BWG.A."

"This was a limited false positive issue with our antivirus protection," a Microsoft representative said Monday. "After we became aware of the issue, we released a new antivirus signature that resolved the issue for our customers on Sunday evening."

The problem started last week, when Google made some changes to its Gmail Web site, Microsoft said. The software maker is reviewing its procedures and processes in order to minimize the occurrence of further false positives, the Microsoft representative said.

Google did not immediately respond to a request for comment.

False positives happen occasionally with security software. For example, McAfee's security tools earlier this year flagged Microsoft's Excel, and other legitimate applications on users' PCs, as viruses. Also, Symantec this summer identified a Church of England software program as spyware.

Windows Live OneCare is Microsoft's first consumer antivirus product, released late May. The Gmail issue isn't the first problem it has had. During testing, OneCare was found to disable Absolute Software's Computrace LoJack, an application that functions like a homing device to help recover a laptop after it has been lost or stolen.

Typically, false positives can be fixed by updating the signature files in security applications. These signatures are the rules used by the security program to identify malicious software.