Microsoft investigates Windows 11 boot failures after January updates

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

KB5074109 Update Causes Boot Failures on Windows 11 Devices

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

I got an "unmountable_boot_volume", now I don't know what to do...

Here's the pitiful story:<P>To install SQL2000 SP2 I tried to unpack the archive after dloading from ms.com. I hear the HD spindown (or shutdown- very odd- and not anything else, just the HD) then ...
Ars Technica

Support Request: Unmountable Boot Volume

My Dell Precision M90 laptop has resorted to giving me BSoD with "Unmountable Boot Volume." I have followed MicroSoft's advice and accessed the Repair console, from which I am running "chkdsk ...