unmountable boot volume

Microsoft has confirmed that a chain of updates — a failed December 2025 security update that left some machines in an “improper state,” followed by the January 13, 2026 cumulative update (KB5074109) — is responsible for a limited but serious set of Windows 11 boot failures that present as...

Microsoft has confirmed that the Windows 11 January 2026 cumulative update (tracked as KB5074109) is associated with a small but serious set of machine failures that can leave some physical PCs unable to boot, showing the UNMOUNTABLE_BOOT_VOLUME stop code and a black screen that requires manual...

Microsoft has acknowledged a troubling regression in its January 2026 Windows 11 cumulative update: a limited but serious set of physical PCs can fail to complete startup after installing the update, presenting the stop code UNMOUNTABLE_BOOT_VOLUME and a black “Your device ran into a problem”...

Microsoft has confirmed that some Windows 11 machines are failing to boot after installing the January 2026 security update, and administrators and enthusiasts are still left picking up the pieces while Microsoft’s engineering teams investigate. Background Microsoft shipped its January 13, 2026...

Some Windows 11 systems are failing to boot after Microsoft’s January 2026 cumulative update, leaving affected PCs stuck at an early black error screen with the stop code UNMOUNTABLE_BOOT_VOLUME and forcing manual recovery or — in worst cases — a reinstall. Microsoft has acknowledged a limited...

Microsoft’s January 2026 security rollup for Windows 11 has left a small but significant subset of physical PCs unable to complete startup, producing the classic UNMOUNTABLE_BOOT_VOLUME stop code and forcing manual recovery while Microsoft investigates the cause. Background The January Patch...

Microsoft’s January 2026 cumulative for Windows 11 has turned into a high-stakes update incident: a mandatory security rollup released on January 13 is linked to a small but serious set of machines that fail to complete startup—displaying the stop code UNMOUNTABLE_BOOT_VOLUME and the message...

Microsoft released its January cumulative for Windows 11 (KB5074109) on January 13, 2026 — and within days a series of serious regressions began surfacing, from brief black screens on some Nvidia-equipped machines to full startup failures that print UNMOUNTABLE_BOOT_VOLUME (Stop Code 0xED) and...

Microsoft has confirmed that its January cumulative update for Windows 11 is linked to a small but serious class of failures that can leave some physical PCs unbootable—often with the UNMOUNTABLE_BOOT_VOLUME stop code—forcing recovery via WinRE or, in worst cases, a clean reinstall. Background...

Microsoft’s January Windows 11 cumulative security update has produced a worst‑case outcome for a small but painful subset of PCs: after installing KB5074109 (the January 13, 2026 LCU/SSU bundle), some physical machines fail to complete startup, showing the UNMOUNTABLE_BOOT_VOLUME stop code and...

Microsoft has confirmed that its January 13, 2026 cumulative update for Windows 11 (KB5074109) is tied to a serious, if currently limited, regression that can leave physical PCs unbootable with the stop code UNMOUNTABLE_BOOT_VOLUME — a black-screen failure that requires manual recovery through...

Microsoft has confirmed that a limited number of Windows 11 systems that received January’s cumulative update (KB5074109) — and some of the subsequent out‑of‑band patches — are failing to complete startup and are showing the UNMOUNTABLE_BOOT_VOLUME stop code, forcing manual recovery on affected...

A routine Patch Tuesday release on January 13, 2026 has left a significant portion of classic Outlook users scrambling: the Windows 11 cumulative update KB5074109 and a separate Outlook Current Channel build have each introduced regressions that render parts of the traditional Outlook experience...

Microsoft has confirmed a troubling regression in its January 2026 Windows 11 servicing wave: a limited—but serious—set of devices that installed the January cumulative update (KB5074109) are failing to complete startup with a stop code of UNMOUNTABLE_BOOT_VOLUME, leaving some machines unusable...

Microsoft's January security rollup for Windows 11 has once again rattled the update ecosystem: after a series of rollback updates and emergency fixes, a subset of users who installed KB5074109 report an even darker outcome than the earlier shutdown and sleep bugs — some PCs now fail to boot...

Microsoft has opened an investigation after a subset of Windows 11 devices running the 25H2 servicing branch failed to boot following the January cumulative update, producing an early-stop error of UNMOUNTABLE_BOOT_VOLUME that in many cases left systems unusable until the offending update was...

Microsoft's first cumulative Windows 11 update of 2026 — delivered as KB5074109 on January 13 — has left a broad trail of disruption: critical security fixes were installed, but several high-impact regressions followed, forcing Microsoft into rapid damage control with out‑of‑band patches and...

A routine January Patch Tuesday rollup (KB5074109) accidentally left parts of Microsoft’s classic Outlook experience unstable for a measurable number of users, triggering freezes, lingering OUTLOOK.EXE processes, lost Sent Items and a rapid sequence of follow‑up fixes and mitigations from...

I have seen other references but typically with older Windows. This is Windows 10 Pro which has just been delivered to me on a (new to me but refurbed ) PC. Athlon CPU, 8gb memory, 250 ssd and 500 gb hdd. I have been trying to create a functional PC for about 2.5 days. When I got the PC I...

I am working on a Dell Inspiron 2205 all in one touch screen running Win 7 home premium 64 bit with 4 gb ram and 500 gb hd. The original problem was lock ups on an irregular basis. Of course I eliminated virus and malware infection. I ran several diagnostic programs including memtest and...