Well, it's one way to see off the competition: on Friday, Microsoft's Security Essentials antivirus software flagged Google Chrome as malware and wiped it from the PCs of thousands of people.
The antivirus software appears to have identified Chrome as the PWS:Win32/Zbot virus, a variation of the Zeus trojan, and automatically blocked it or even removed it from customers' machines. Around 3,000 users were affected.
Many people suspected that the move was simply Microsoft's way of seeing off the browser competition, with Chrome rapidly gaining ground on Internet Explorer.
"Was there really a problem, or is this just a way for Microsoft to stick it to Google?" asked one user on a Google support forum. "This is a conspiracy on behalf of Microsoft to take down Google!" claimed another.
Microsoft, though, has apologised, and quickly released an update. "Affected customers should manually update Microsoft Security Essentials (MSE) with the latest signatures," it says.
"To do this, simply launch MSE, go to the update tab and click the Update button, and then reinstall Google Chrome."
Meanwhile, Google's released an update to automatically repair Chrome for affected users.
"The Chrome Stable channel has been updated to 14.0.835.187, and the Beta channel has been updated to 15.0.874.58," says the company's Jason Kersey. "These updates should help repair Chrome installs that were broken due to the issue with Microsoft Security Essentials."
However, many affected users are reporting that they've lost their bookmarks.