Microsoft says it 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, with the fix ...

A fresh wave of Windows 11 update trouble is making the rounds, and this one is about as disruptive as it gets: some PCs reportedly can’t boot after installing the latest January 2026 security update.

January update triggered UNMOUNTABLE_BOOT_VOLUME BSODs, leaving some Windows 11 PCs unable to boot. A failed December update rollback left devices in an improper state, and January's patch worsened it ...