A new security update meant to provide protection against the security vulnerabilities Spectre and Meltdown for Windows 7, 8.1, and 10 is causing systems to freeze up and hang on startup. According to the Windows 7 and 8.1 update history pages, the new update causes systems using certain antivirus software to stop responding shortly after startup. For Windows 10 systems on the other hand, the update history page only lists ArcaBit as an antivirus software that is having issues with the new update. Microsoft added that they are temporarily blocking the update on Windows 7 and 8.1 systems that have Avira and Sophos installed until a proper solution is available. The updates causing the issue are KB4493472 and KB4493448 on Windows 7, KB4493467 and KB4493446 on Windows 8.1, and KB4493509 on Windows 10.
Source: The Star April 15, 2019 06:22 UTC