Windows 11 KB5074109 Jan 2026: Security Rollup, AVD Issue, and Deployment Guide

Microsoft’s January 13, 2026 cumulative update for Windows 11—KB5074109—delivers a heavyweight security rollup and several quality fixes, but it also introduced at least one verified enterprise-impacting regression and a raft of community-reported compatibility problems that make careful rollout planning essential.

Background / Overview​

KB5074109 is the January 2026 Patch Tuesday cumulative update for Windows 11 versions 24H2 and 25H2, moving affected systems to OS build 26100.7623 (24H2) and 26200.7623 (25H2) after installation. The package combines the Latest Cumulative Update (LCU) with servicing-stack components and includes broad security hardening, platform fixes, and staged UI/feature rollouts. At a glance, the release does three things simultaneously:

• Patches a large security surface, closing more than one hundred vulnerabilities in January’s security baseline.
• Fixes device-level quality problems—most notably a Neural Processing Unit (NPU) idle-power bug that could reduce battery life on certain AI-enabled laptops.
• Surfaces staged Copilot-era UI and File Explorer improvements, while also triggering one verified regression that affects Azure Virtual Desktop (AVD)/Windows 365 connectivity on some managed clients.

This article explains what KB5074109 actually changes, examines verified and credible community-reported problems, analyzes who should (and should not) install it right now, and provides a practical deployment and remediation playbook for IT teams and power users.

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What KB5074109 changes — the technical summary​

Security baseline and CVE coverage​

KB5074109 is part of Microsoft’s January 2026 security baseline. Independent reporting and Microsoft’s update pages indicate the month’s security bundle addresses roughly 112–114 vulnerabilities, including multiple zero-days and several critical remote-code-execution issues. This update closes active exploit paths in core components such as Desktop Window Manager and refreshes some components used by third parties. These are substantive security mitigations and the primary reason many organizations will prioritize installation.

Build numbers and packaging​

After applying KB5074109 devices will report the following builds:

• Windows 11 24H2 → 26100.7623
• Windows 11 25H2 → 26200.7623

The package is delivered as a combined SSU+LCU bundle in Windows Update and is available as offline MSU/catalog entries for staged deployment. Note that once the servicing stack update (SSU) portion is applied, it persists and complicates simple rollbacks.

Notable non-security fixes and feature rollouts​

• NPU power-state fix: Devices with Neural Processing Units that were staying powered while the host was idle now get corrected power-state transitions, reducing idle battery drain on affected laptops and handhelds.
• File Explorer — “Recommended” feed: A new Recommended section in File Explorer Home surfaces frequently used or recently downloaded files. The experience is tied to a Microsoft account and can be toggled in File Explorer Options; availability is staged and account/telemetry gated. This capability traces to earlier previews and is now visible more broadly in the field.
• UI/usability tweaks: Continued Copilot-era feature rollouts—e.g., taskbar “Share with Copilot” integrations, improved dark-mode consistency, a Start Menu account manager, and support for dragging Start pinned apps to the taskbar—are present but gradually gated. Not all devices will see these immediately even if KB5074109 is installed.
• Secure Boot certificate rollout: The update introduces a phased mechanism for delivering new Secure Boot certificates to eligible devices, based on successful update telemetry, to prevent mass breakage when older UEFI certificates expire.

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Verified critical regression: AVD / Cloud PC authentication failures​

The single most consequential, verified regression in KB5074109 affects enterprise users connecting to Azure Virtual Desktop (AVD) and Windows 365 Cloud PCs using the Windows App. Within hours of the Jan 13 rollout, administrators and users began reporting immediate authentication failures when launching AVD sessions from the Windows App: dialogs such as “An authentication error has occurred (Code: 0x80080005)” appear and sessions fail before a connection is established. Microsoft acknowledged the problem in the KB’s Known Issues section and published mitigations. Why this matters

• The failure occurs at the client’s credential prompt or SSO handshake stage, so the cloud service itself (AVD host/gateway) is generally not the root cause—this is a client-side regression that prevents session negotiation from progressing. That makes it a synchronous outage for many enterprise remote workers.
• Uninstalling the LCU can restore connectivity, but that removes the update’s security fixes; Microsoft therefore offered a safer mitigation path (Known Issue Rollback, KIR) so administrators can restore functionality without fully removing the security baseline.

What Microsoft and administrators recommend (short)

• Apply Microsoft’s Known Issue Rollback (KIR) artifact for your Windows version via Group Policy/Intune and reboot targeted devices. This surgically disables the small change that caused the regression while preserving other security fixes.
• If you cannot apply KIR quickly, instruct affected users to use the classic Remote Desktop client (MSRDC) or the AVD web client (browser) as temporary workarounds.
• Pause broad deployment to critical rings until the out-of-band fix or next servicing update is released.

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Community-reported issues: gaming performance, display glitches and USB formatting​

Beyond the AVD regression (which Microsoft acknowledged), community telemetry and forums have captured a variety of issues that are credible signals—some verified in repro cases, others anecdotal and heterogeneous.

Gaming / GPU anomalies (NVIDIA and others)​

• Multiple community threads and Reddit posts report brief black screens, display freezes, and game FPS drops after installing KB5074109, particularly on systems with NVIDIA GPUs. Anecdotes cite single-digit to double-digit FPS losses in some titles, and some users observed short blackouts lasting a few seconds that then recover without a full crash.
• Vendor response and context: GPU/driver ecosystems are highly sensitive to kernel and OS servicing changes. Historically, similar cumulative updates have exposed timing or driver-path interactions that required vendor hotfix drivers or firmware updates to fully resolve. That precedent makes these post-update GPU reports plausible and worthy of careful testing.

Practical guidance for gamers and high-performance users:

• Do not install KB5074109 immediately on your primary gaming rig. Instead, pilot on a secondary machine or a system image snapshot.
• If already installed and you see performance regression, update to the latest GPU driver from NVIDIA/AMD, test again, and if the problem persists, roll back to the previous known-good driver. Community reproductions indicate driver rollback often removes the immediate symptoms.
• Preserve a system restore point or backup so you can revert quickly; consider deferring the update in Windows Update for Business until vendor guidance is posted.

USB formatting / FAT32 reports (unverified)​

Some outlets and community reports mention Windows failing to format USB drives as FAT32 after the update. These reports are currently heterogeneous and lack consistent repro steps across diverse hardware; general USB-format issues are a long-standing Windows troubleshooting domain (DiskPart, third-party format tools, write-protect flags), but a direct causal link to KB5074109 is not established by Microsoft at this time. Treat these reports as possible but not yet vendor-validated.

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Strengths of KB5074109 — what Microsoft got right​

• Large security coverage: The update consolidates Microsoft’s January security baseline, addressing over a hundred CVEs including actively exploited issues in core Windows components—this materially reduces attack surface for both consumer and enterprise fleets.
• NPU battery fix: Correcting NPU idle-power behavior addresses a real-world battery drain on modern AI-capable devices; for affected laptop users this will restore meaningful unplugged run time. This demonstrates Microsoft’s attention to contemporary silicon features.
• Managed mitigation (KIR): Microsoft’s rapid publication and distribution of a Known Issue Rollback for the AVD regression is operationally mature: KIR lets enterprises surgically reverse only the offending change while retaining other security fixes. That capability dramatically reduces the security-vs-availability trade-off for managed fleets.
• Secure Boot certificate staging: Preparing a telemetry-driven certificate rollout reduces the risk of mass failures when older UEFI certificates expire—this is a prudent, phased approach to a potentially catastrophic platform change.

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Weaknesses and risks — where KB5074109 needs caution​

• Client-side regressions with outsized impact: The AVD credential-prompt regression is a reminder that small client changes that touch authentication or SSO flows can create immediate, high-severity outages for remote-work populations. Monthly cumulative cadence compresses the time for catching these cross-stack issues in pre-release testing.
• Heterogeneous hardware/driver interactions: GPU and other low-level driver stacks respond differently to OS updates; short black screens and FPS regressions reported by the community show that such interactions are alive and well. Vendor coordination and quick driver hotfixes are important but not instantaneous, making head-of-line risk real for power users.
• Rollback complexity: Because SSUs persist, true rollback to a pre-update baseline is often non-trivial. Administrators must plan KIRs or accept that uninstalling the LCU removes critical security fixes. This complicates golden image management and offline servicing pipelines.
• Community vs. vendor verification gap: Many gaming and USB-formatting claims are community-sourced. They are credible signals, but not yet fully verified by hardware vendors or Microsoft. Treat performance numbers (e.g., “exactly 20 FPS loss on NVIDIA cards”) as anecdotal until proven with controlled benchmarks.

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Deployment and remediation playbook (practical steps)​

For enterprise administrators (AVD/Windows 365 environments)​

• Immediately inventory endpoints: identify devices with KB5074109 installed via winver.exe or DISM:
  DISM /online /get-packages | findstr 5074109.
• Pause further rollout to production rings until pilot validation passes.
• If users report AVD sign-in failures, deploy Microsoft’s Known Issue Rollback (KIR) package for your Windows version via Group Policy or Intune and reboot machines—this is the recommended mitigation that preserves the rest of the security baseline.
• In parallel, communicate alternatives to end users: use the AVD web client or the classic Remote Desktop client while affected devices are being remediated.
• Monitor Microsoft’s Release Health and vendor advisories for an out-of-band fix and validate once a corrected package is published.

For IT admins and developers (testing and pilot checklist)​

• Ensure test rings include:
• NPU-equipped laptops to verify battery behavior.
• AVD/Cloud PC users to validate authentication and SSO flows.
• Representative gaming rigs with NVIDIA/AMD GPUs to detect display regressions.
• Collect logs and frame-time telemetry during gaming repro attempts—if vendors ask for system info (msinfo32), provide it for reproducibility. Community reports indicate vendors may request systeminfo to triage black-screen incidents.
• Validate third-party security tools (EDR/AV) do not flag updated components (e.g., WinSqlite3.dll). Coordinate with vendor support when necessary.

For consumers and gamers​

• Home users concerned primarily about security should install KB5074109 after backing up critical data—most consumer environments are very unlikely to be affected by the AVD regression.
• Gamers: defer update for 7–14 days on machines used for competitive play; pilot on a secondary box or create a disk image for quick rollback. Update GPU drivers before or after the OS update and test critical titles.
• If you experience performance or black-screen issues, test a driver rollback or clean driver reinstall (DDU) and, if necessary, restore a system image or uninstall the KB as a last resort.

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How to check your system and (if necessary) roll back safely​

• Confirm OS build: run winver.exe and verify you see 26100.7623 or 26200.7623.
• If AVD auth fails and KIR is not yet applied by your admin team, use the AVD web client or classic Remote Desktop client; these are vendor-supported temporary workarounds.
• To uninstall the LCU as an emergency measure (last resort only), use DISM to enumerate and remove the package—understand this removes security fixes. Example (replace PACKAGE_ID with the actual identifier):
• DISM /online /get-packages | findstr 5074109
• DISM /online /remove-package /packagenameACKAGE_ID
  This should be considered temporary: prefer deploying KIR if available.

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Final assessment — balance security vs. stability​

KB5074109 is a consequential cumulative update: it fixes a large tranche of security issues, addresses a tangible battery problem on certain AI-capable hardware, and nudges some Copilot-era UI features out of preview. Those are meaningful wins and, for many consumers and non-AVD enterprises, the patch should be applied promptly after routine backups.
However, the validated AVD credential-prompt regression and widespread community telemetry of GPU/display anomalies mean the update is not a drop-in for all environments. For organizations that rely on AVD/Cloud PCs, the current operational advice is clear: pause broad deployment, apply Microsoft’s Known Issue Rollback where required, and validate the fix once Microsoft ships an out-of-band update. For gamers and high-performance users, pilot and verify GPU behavior before fleet-wide installation on primary rigs. KB5074109 is a reminder of an immutable truth in platform servicing: monthly security cadence reduces exposure windows but also shortens the time for catching complex cross-stack regressions in the wild. The right operational posture is disciplined pilot rings, KIR‑ready mitigations for enterprises, and a careful, evidence-driven approach for power users who depend on real-time graphics performance or cloud-desktop availability.

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In sum: install KB5074109 if you prioritize the January security baseline and are not dependent on AVD or sensitive GPU-driven workflows; if you run AVD/Cloud PC environments or maintain gaming rigs, delay broad deployment, pilot carefully, and prepare to apply Microsoft’s KIR or vendor driver fixes as needed.

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Source: filmogaz.com Windows 11 Update: KB5074109 Fixes Critical AVD and Gaming Bugs