Windows 11 KB5083769 causes boot loops and recovery errors for some users. Systems fail to start, with no official fix yet.

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 An outdated BIOS is the primary cause of the 0xC1900101 ...

Some Windows 11 PCs hit BitLocker recovery after the April 2026 update. Here's what's causing it and how to fix this problem.