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

It's not just January's one.

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

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

Round and round we go.

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

Everyone knows you need to keep your operating system up to date, but what happens when a company botches the update and ...

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 ...

Neowin also notes another dark side to this latest issue. “Interestingly, Microsoft came up with a technical solution for ...

A fresh wave of Windows 11 update trouble is making the rounds, and this one is about as disruptive as it gets: some PCs reportedly can’t boot after installing the latest January 2026 security update.

Microsoft issues second emergency patch for Windows this month - update your PC today ...

So my dad's system (Duron 1.1, XP Home, 1GB memory) refused to boot to normal Windows or Safe Mode, stopping with the beloved 0xED Unmountable Boot Volume.<BR><BR>I booted off the installation CD and ...