A Windows security update bug has prevented some Windows 11 24H2 and 25H2 users from booting into their PCs, requiring them ...

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

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

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

Windows 11 runs into another disastrous bug with its latest update — Microsoft admits an 'issue in which devices are failing ...

Microsoft is investigating reports of serious boot failures affecting Windows 11 devices following the January 2026 security ...

Microsoft is shifting focus to fixing Windows 11 performance and reliability after months of buggy updates, boot failures, ...

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

The January update for Windows 11 has been met with considerable backlash, primarily due to reports of PCs refusing to shut down and displaying critical errors. A particularly alarming issue is the ...

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Microsoft has linked recent reports of Windows 11 boot failures after installing the January 2026 updates to previously failed attempts to install the December 2025 security update, which left systems ...

If you are encountering the 0xC1900101-0x40021 Windows 11 upgrade error, execute the solutions given below. An outdated BIOS is the primary cause of the 0xC1900101 ...