Scores of others reported the same behavior on their Windows PCs running Microsoft's Security Essentials -- its free, consumer-grade antivirus software -- as well as Forefront, the antivirus product designed for enterprises.

Microsoft issued a corrected definition file around 10 a.m. PT Friday, about three hours after users began reporting the false positive on Google's support forum.

Several bloggers, including ZDNet's and , reported the problem earlier today.

Microsoft has acknowledged the gaffe, and said approximately 3,000 users were affected.

"An incorrect detection for PWS:Win32/Zbot was identified and as a result, Google Chrome was inadvertently blocked and in some cases removed from customers PCs," Microsoft said in a statement posted to the of its malware research center. "We have already fixed the issue..., but approximately 3,000 customers were impacted."