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

win xp unmountable boot volume?

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 ...
Windows Latest

Microsoft confirms Windows 11 KB5074109 January update BSOD, boot issues on some PCs (commerical)

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