Windows 11 KB5077181 fixes boot failures linked to failed updates

Source: Bleeping Computer

Overview

Microsoft has resolved a Windows 11 bug that caused some commercial systems to fail to boot with an UNMOUNTABLE_BOOT_VOLUME error after installing recent security updates. The fix is delivered in the February 2026 Patch Tuesday update.

The boot issue, previously linked to failed December 2025 updates, affected a limited number of commercial Windows 11 devices running versions 25H2 and 24H2. According to a private enterprise advisory seen by Susan Bradley of Ask Woody, the problem is fully resolved in the Windows 11 KB5077181 security update released on February 10, 2026.

Impacted devices suffered boot failures after installing the January 13, 2026 security update KB5074109 (or later updates), displaying a black screen and the message:

“Your device ran into a problem and needs a restart. You can restart.”

At that point, the systems were unable to boot and required manual recovery to restore functionality.

Microsoft previously confirmed the issue was caused by the failed installation of the December 2025 security update, which left devices in an improper state after the installation rolled back. Attempting to install future Windows updates on devices in this state could render the system unbootable.

The problem affected only physical devices running Windows 11 25H2 and 24H2; no reports indicated impact on home users or virtual machines.

Fix Delivered in February Patch Tuesday Update

Microsoft initially released a resolution in the optional non‑security preview update KB5074105 on January 29, 2026, which helped prevent additional systems from becoming affected.

The issue is now fully resolved in the Windows 11 KB5077181 update released during the February 2026 Patch Tuesday and later updates.

“This issue is fully resolved in the Windows security update released on February 10, 2026 (the Resolved KBs listed above), and later updates,” reads Microsoft’s advisory.

Remediation for Unbootable Systems

Devices that became unbootable before the fix may still require additional remediation. Microsoft advises enterprise customers whose devices remain affected to contact Microsoft Support for Business for assistance restoring system stability.

It is unclear why Microsoft did not share this advisory publicly, as it does for other known Windows issues.