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 An outdated BIOS is the primary cause of the 0xC1900101 ...

The boot issue, which Microsoft previously investigated and linked to failed December 2025 updates, affected a limited number of commercial Windows 11 devices running versions 25H2 and 24H2.

A clean Windows install is a great way to keep your PC feeling snappy. However, every time you do this, certain critical features are reset to their Microsoft defaults—including some that could lock ...

Microsoft is investigating reports that some Windows 11 devices are failing to boot with "UNMOUNTABLE_BOOT_VOLUME" errors after installing the January 2026 Patch Tuesday security updates. The issue ...

Microsoft is rolling out critical Secure Boot certificate updates to Windows 11 systems, with PCWorld reporting that current certificates expire in June 2026. Users must install quality updates and ...

Windows 11 now shows Secure Boot alerts to help users prepare for 2026 certificate expiration and avoid security issues.