If you weren't able to shut down your Windows 11 device recently, Microsoft has rolled out an emergency fix addressing a couple of critical bugs that popped up with its latest January 2026 Windows security update.

Microsoft's January security updates for Windows 11 also appear to be disrupting Outlook. Microsoft is investigating problems with POP mail accounts.

Windows 11 KB5074109 causes a black screen on some PCs, including those with an Nvidia GPU, and also freezes Outlook if you use POP.

Microsoft’s latest Windows 11 security update was meant to harden PCs against stealthy firmware attacks. Instead, it has triggered a fresh headache: some systems now refuse to power off properly, looping back to the desktop instead of shutting down.