Windows 11 KB5074109 (January 2026 Update) is causing major issues on some PCs, and Microsoft has more details to share.

Windows 11 January 2026 updates may cause boot failures on some PCs. Microsoft is investigating issues linked to KB5074109.

Round and round we go.

Microsoft is investigating reports that some Windows 11 devices are failing to boot with "UNMOUNTABLE_BOOT_VOLUME" errors ...

A Windows security update bug has prevented some Windows 11 24H2 and 25H2 users from booting into their PCs, requiring them ...

Microsoft is aware of an alleged issue that leaves PCs unable to boot and requires manual recovery after Windows 11 January ...

Windows install floppies and discs have gone the way of the dodo, but it still pays to keep a copy of the OS on a USB drive. Here's how to make your own.

Microsoft is shifting focus to fixing Windows 11 performance and reliability after months of buggy updates, boot failures, ...

Microsoft has linked recent reports of Windows 11 boot failures after installing the January 2026 updates to previously failed attempts to install the December 2025 security update, which left systems ...

Some machines are failing to start after security updates, prompting yet another Microsoft investigation Microsoft is ...

Microsoft is investigating reports of serious boot failures affecting Windows 11 devices following the January 2026 security ...

When Windows won’t boot up, it can be a disturbing experience. But that moment passes quickly, and you must decide how to get past this (hopefully) temporary hiccup. Fortunately, there are plenty of ...