Gmail's popularity may be viral, but the e-mail software is not a virus--despite a Microsoft alert.

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.

Full story: CNET News.com