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

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

Windows 11’s latest update drama: KB5074109 breaks things, and the uninstall process breaks too.

Windows 11 shutdown bug explained with causes, fixes, and workarounds to stop restarts, battery drain, and failed power-offs after updates.

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

Windows 11 users are experiencing issues with a Firewall configuration error when using Windows Firewall with Advanced Security, following the June 26 KB5060829 ...

Microsoft’s first Windows 11 security update of 2026 broke shutdowns and some Remote Desktop sign-ins. Microsoft has released ...

Windows Update error 0x80240069 has been occurring recently when installing KB5063878 using enterprise tools like WSUS or SCCM, but it works fine when using Windows ...

Microsoft confirmed that the KB5074109 January Windows 11 security update causes the classic Outlook desktop client to freeze ...

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 An outdated BIOS is the primary cause of the 0xC1900101 ...