Microsoft Shares More Details About Windows 11 Patch Tuesday Causing Boot Failures on Business PCs

Microsoft must be hoping this month passes by as soon as possible, as nothing seems to be going right with Windows updates. If you use Windows 11, I’m sure you’re aware of what I’m talking about. For the unaware, around mid-January, Microsoft released the first Patch Tuesday update, KB5074109, for Windows 11. Unfortunately, users started reporting that the update was causing serious bugs and issues on their systems.

The issues were quite widespread, so much so that the company had to release two emergency updates (1) (2) in the span of two weeks to contain some of the problems. Among the ones troubling multiple users was boot failure. After confirming the issue last week, Microsoft has now shared some more details about it. For those unaware, the affected systems crash into a black screen of death, displaying an “unmountable boot volume” error. According to Microsoft, the issue is limited to commercial PCs, sparing consumer systems for now.

Microsoft shares more details about the boot failure bug triggered by the latest Patch Tuesday update in Windows 11

That said, the situation remains grim for enterprise users. Microsoft admits there is no simple fix for systems already affected. Neowin, without citing a source, now reports Microsoft saying that the issue occurs when devices fail to install the December 2025 security update and are left in an “improper state” after the update rollback. Apparently, installing newer Windows updates while in this state can cause the system to become completely unbootable. Here’s what the news outlet quoted Microsoft as saying about the issue:

Recent investigations have determined this issue can occur on devices that failed to install the December 2025 security update and were left in an improper state after rolling back the update. Attempting to install Windows updates while in this improper state could result in the device being unable to boot. We are working on a partial resolution that will prevent additional devices from resulting in a no-boot scenario if they try to install an update while in this improper state. However, this partial resolution will not prevent devices from getting into the improper state in the first place, nor will it repair devices that are already unable to boot. We continue to investigate why these devices are failing to install Windows updates or potentially getting into this improper state.

Microsoft says the upcoming fixes will only prevent new devices from entering a no-boot scenario. It won’t repair systems that are already stuck in this broken state. While home users are not affected by this specific bug, they are already dealing with plenty of other headaches. More recently, the news outlet also reported, citing user reports on Reddit, that the Windows Smart Control app is breaking Armory Craye on Xbox Ally series.

Are you also facing issues after installing the latest Patch Tuesday update? Let us know in the comments below.