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

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

It's not just January's one.

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

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.

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

Round and round we go.

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 ...

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

greetings. JUST recieved a new dell about a week ago and it has worked great since I got it. it was accidentily unplugged while it was on and now when i re-boot it says: unmountable_boot_volume. I ...

The most recent January Windows Update is broken on a number of PCs, but at least virtual machines don't seem to be impacted.