tldrdailynews.com logo

Windows 11 January 2026 Update Triggers Boot Failures on Some PCs, Prompting Emergency Fix

1 min read
Source: Windows Latest
Windows 11 January 2026 Update Triggers Boot Failures on Some PCs, Prompting Emergency Fix
Photo: Windows Latest
TL;DR

Microsoft says a limited number of devices on Windows 11 24H2/25H2 may fail to boot after installing the January 2026 security update KB5074109, showing a black screen with the UNMOUNTABLE_BOOT_VOLUME stop code. Recovery may be needed via Windows Recovery or a clean install using an ISO; the issue appears limited to certain hardware. An emergency out-of-band update KB5078127 has been released to fix related problems (e.g., Outlook Classic and other app issues), but some glitches remain. If you’re not experiencing issues, no action is required.

Topics:top-newstechnology#boot-failure#kb5074109#kb5078127#technology#unmountablebootvolume#windows-11
Share this article
  1. Microsoft suspects some PCs might not boot after Windows 11 January 2026 Update (KB5074109)  Windows Latest
  2. Microsoft’s first Windows 11 update of 2026 has been a mess  The Verge
  3. Microsoft Confirms Emergency Update For Millions Of Outlook Users  Forbes
  4. Windows 11 update may stop some PCs from booting, warns Microsoft  Windows Central
  5. Microsoft releases second emergency Windows 11 update to fix Outlook crashes  Engadget

Want the full story? Read the original reporting

Read on Windows Latest