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 ...
Ars Technica

Unmountable Boot Volume (0xED)

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 ...