Microsoft has moved to fix a bug in its security software that removed rival Google's Chrome browser from users' computers after labelling it malware.
The Redmond giant fixed the problem within hours on Friday, but Google was even faster, offering a manual fix for the mistake ahead of an automated update over the weekend.
According to Mark Larson, an engineering manager at Google, "the Microsoft Security Essentials tool began falsely identifying Google Chrome as a piece of malware and removing it from people's computers".
"If Chrome is working correctly for you, then there’s no need to take any action," he said in a post on the Google blog.
Microsoft confirmed in a security bulletin that "an incorrect detection for PWS:Win32/Zbot was identified and as a result, Google Chrome was inadvertently blocked and in some cases removed".
Microsoft said it fixed the problem within a few hours, and advised anyone affected to update Microsoft Security Essentials.
"After updating the definitions, reinstall Google Chrome," the company said. "We apologise for the inconvenience this may have caused our customers."
The malware Chrome was mistaken for is a "password-stealing trojan that monitors for visits to certain websites", Microsoft said, adding it can allow limited access to machines and shut down security software.