The faulty update began to be pushed out on Tuesday. It was meant to close a pair of obscure security vulnerabilities, but instead resulted in some computers being unable to restart or load applications. Some people received a “fatal system error,” while others got errors with their antivirus software, implying their PCs were unprotected.
Microsoft addressed the issues in a blog post yesterday and stopped pushing the update. The company says that the issue only affected users who also had certain third-party software installed when they applied the update.
A fix has been rolled out and PCs set to update automatically should download and apply it on their own.