XDA Developers on MSN

Microsoft confirms that a stack of bad Windows updates is causing boot issues

It's not just January's one.
Windows Report

KB5074109 Update Causes Boot Failures on Windows 11 Devices

Windows 11 January 2026 updates may cause boot failures on some PCs. Microsoft is investigating issues linked to KB5074109.

Microsoft investigates Windows 11 boot failures after January updates

Microsoft is investigating reports that some Windows 11 devices are failing to boot with "UNMOUNTABLE_BOOT_VOLUME" errors ...

Some PCs are failing to boot after this month's Windows Update

Another week, another big Windows problem.

Microsoft links Windows 11 boot failures to failed December 2025 update

Microsoft has linked recent reports of Windows 11 boot failures after installing the January 2026 updates to previously failed attempts to install the December 2025 security update, which left systems ...