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

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.

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 ...