Microsoft’s January 13, 2026, safety replace for Home windows 11 has triggered a irritating bug: affected PCs refuse to close down or hibernate, as a substitute restarting.
The difficulty is attributable to KB5073455, which targets OS Construct 22621.6491 on Home windows 11 model 23H2. It was first reported on January 15 and arises from interference with Safe Launch, a virtualization-based safety (VBS) function designed to guard boot processes from firmware threats equivalent to rootkits.
Safe Launch, a part of Home windows’ System Guard suite, verifies the firmware atmosphere throughout startup utilizing hypervisor-protected code integrity.
Isolating the core root of belief measurements prevents persistent malware from tampering with the pre-OS atmosphere. Paradoxically, this month’s patch, supposed to bolster defenses, disrupts the function, blocking correct power-off states on appropriate {hardware}.
Affected Techniques and Scope
The glitch impacts solely the Enterprise and IoT editions of Home windows 11 23H2, sparing the patron Residence and Professional variants. No server platforms, equivalent to Home windows Server, face disruptions.
Microsoft confirmed the issue by way of its assist portal, final up to date January 15 at 19:01 PT. Techniques should have Safe Launch enabled, a standard setup in high-security enterprise deployments that depend on VBS to satisfy compliance requirements equivalent to NIST or zero-trust architectures.
Admins in regulated sectors, together with finance and authorities, report the problem throughout fleets, elevating considerations over energy administration reliability.
Whereas not a vulnerability itself, the bug exposes dangers: gadgets caught in restart loops drain batteries sooner, probably resulting in information loss or unattended uptime that amplifies publicity to unpatched threats.
Microsoft presents a short lived repair for shutdowns by way of Command Immediate: launch cmd from the Search bar and run shutdown /s /t 0. This forces an instantaneous power-off, bypassing the GUI failure. Hibernation lacks a workaround; customers should save work and go for full shutdowns to stop surprising energy loss.
The corporate guarantees a repair in an upcoming replace and urges IT groups to observe Home windows Replace channels. Within the interim, disabling Safe Launch by way of Group Coverage (Laptop Configuration > Administrative Templates > System > Machine Guard) restores performance however weakens boot integrity—a trade-off for menace hunters weighing the dangers of firmware assault vectors.
This incident underscores the double-edged sword of month-to-month Patch Tuesday rollouts. As enterprises patch for zero-days, such regressions spotlight the necessity for staged testing, particularly on security-hardened configs.
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