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.
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 An outdated BIOS is the primary cause of the 0xC1900101 ...
Share on Facebook (opens in a new window) Share on X (opens in a new window) Share on Reddit (opens in a new window) Share on Hacker News (opens in a new window) Share on Flipboard (opens in a new ...
Microsoft has released the KB5074105 preview cumulative update for Windows 11 systems, which includes 32 changes, including fixes for sign-in, boot, and activation issues. KB5074105 is an optional ...