Windows 11 January 2026 Security Update: KB5074109 and KB5073455 Fix AI PC Battery Drain

Windows 11 is getting its first big security refresh of 2026, with new cumulative updates KB5074109 and KB5073455 rolling out to supported devices. These releases focus on battery life for AI PCs, Secure Boot hardening, and a slate of reliability and security fixes for mainstream Windows 11 versions.

How to install the January 2026 Windows 11 updates

Installing KB5074109 or KB5073455 is straightforward on most PCs, and you can use either the standard Windows Update flow or download the packages manually if needed.​

Method 1: Using Windows Update (recommended)

For most home users and laptops, this is the easiest way to grab the January 2026 patches.​

1. Open Settings from the Start menu or by pressing Windows key + I.​

2. Select Windows Update in the left sidebar.

3. Click Check for updates and wait while Windows scans.​

4. Look for one of these entries, depending on your version:​

   • “2026-01 Security Update for Windows 11 (KB5074109)” on 24H2/25H2.

   • “2026-01 Security Update for Windows 11 (KB5073455)” on 22H2/23H2.

5. Click Download & install, then restart when prompted to complete the installation.​

Method 2: Using Microsoft Update Catalog (manual install)

If Windows Update fails or you manage multiple machines, you can grab the .msu files directly.​

1. Go to the Microsoft Update Catalog website and search for KB5074109 or KB5073455​

2. Download the correct package for your edition (Windows 11) and architecture (x64 or ARM64).windowslatest+1​

3. Double‑click the downloaded .msu file to launch Windows Update Standalone Installer and follow the prompts to install.​

4. Restart the PC when asked to finish applying the update.​

How to confirm the update installed

After rebooting, you can verify that KB5074109 or KB5073455 is actually installed.​

• Open Settings > Windows Update > Update history to see recent updates along with their KB numbers and install dates.​

• Alternatively, open Control Panel > Programs > Programs and Features > View installed updates to check the installed quality updates list.​

What’s new in KB5074109 (24H2 / 25H2)

For newer Windows 11 releases (24H2/25H2), KB5074109 is the January 2026 security update and the first cumulative update of the year. It is primarily a security rollup, but it also packs a few important quality fixes that matter a lot for AI PCs.​

Pertinent highlights for 24H2/25H2 include:

• NPU battery drain fix on AI PCs: KB5074109 addresses an issue where the NPU (neural processing unit) could stay powered on when idle, causing unnecessary power draw and hurting battery life on Copilot+ and other AI‑accelerated Windows 11 devices. For anyone using AI‑enhanced laptops, this is the single most noticeable change, since it directly impacts how long your system can run unplugged during a normal workday.​

• Security and platform hardening: The update bundles all security patches from January’s Patch Tuesday for the newer development branch, including kernel, driver, and subsystem fixes that are not individually documented but are called out in Microsoft’s Security Update Guide for January 2026.​

If your audience cares about AI PCs specifically, this is an easy angle: the first Windows 11 update of 2026 finally cleans up some of the growing pains around NPU power management.

What’s new in KB5073455 (22H2 / 23H2)

For the mainstream Windows 11 crowd on 22H2 and 23H2, KB5073455 (OS build 22631.6491) is the January 13, 2026 cumulative update. It rolls in both January’s security patches and the non‑security improvements that shipped as an optional preview in December 2025.​

Important changes in KB5073455 include:

• Legacy modem driver removal: Microsoft is removing support for a set of very old modem drivers (agrsm64.sys, agrsm.sys, smserl64.sys, smserial.sys), which means any hardware still depending on those specific drivers will simply stop working after the update. This only impacts niche legacy setups, but it is worth flagging for enterprise and lab environments that hang on to ancient hardware.​

• RDP reliability fix: A display‑kernel issue that could cause Remote Desktop Protocol (RDP) connections to fail—sometimes requiring a reboot to reconnect—has been fixed, which is important for remote workers and admins who live inside RDP sessions.​

• App crash fixes when typing: Apps like Outlook, Teams, Edge, Chrome, and Excel could close unexpectedly when entering text, and KB5073455 specifically addresses this input‑related crash bug. That one will be very visible to information workers and might reduce those random “everything just crashed while I was typing” moments.​

Alongside those, the servicing stack is updated via KB5071963 to ensure future Windows updates install more reliably. This is one of those invisible plumbing updates that quietly reduces install failures and rollbacks over time.​

Secure Boot, WinSqlite3, and security focus

Beyond the headline quality fixes, KB5073455 also introduces a more nuanced change to how Windows pushes out new Secure Boot certificates. With Secure Boot certificates set to start expiring in mid‑2026, Microsoft is laying the groundwork so devices can transition without breaking boot.​

Notable security‑related points:

• Secure Boot certificate rollout logic: Starting with this update, Windows quality updates include a subset of “high confidence” device targeting data that identifies which devices are eligible to automatically receive new Secure Boot certificates. Devices only get the new certificates after demonstrating a good update track record, which gives Microsoft a safer, phased deployment model that avoids bricking machines that have patching or firmware issues.​

• WinSqlite3.dll update: The Windows core component WinSqlite3.dll has been updated, addressing cases where some security tools flagged it as vulnerable. Microsoft is careful to point out that WinSqlite3.dll (a Windows component) is distinct from sqlite3.dll (bundled with individual apps), and any remaining vulnerability detections on sqlite3.dll must be handled by the app developer rather than Windows Update.​

From a security‑writer perspective, this is good material for a short explainer on why Secure Boot certificate rotation matters and how Microsoft is trying to roll it out without chaos.

What admins and users should do

For most home users, the recommendation is simple: install the January 2026 cumulative updates when offered via Windows Update and reboot promptly. That ensures you get the latest Patch Tuesday protections and the AI PC battery fix if you are on newer hardware.​

For IT admins and power users, there are a few extra considerations:

• Plan around legacy hardware: If your environment still uses analog modems or any hardware depending on the removed drivers, treat KB5073455 as a change‑management event and test on representative systems before broad deployment.​

• Monitor Secure Boot certificate behavior: Because Windows now uses device‑health signals to decide when to roll out new Secure Boot certificates, admins should keep an eye on update compliance dashboards and firmware status ahead of the June 2026 certificate expirations.​

• Take advantage of the SSU improvements: The updated servicing stack in KB5071963 is bundled with KB5073455, so once this update is in place, future cumulative updates should be less error‑prone.​

The January 2026 cumulative updates for Windows 11 are more than routine Patch Tuesday housekeeping; they are a meaningful step toward stabilizing AI‑era laptops while quietly preparing the ecosystem for the Secure Boot certificate changes coming in 2026. By installing KB5074109 or KB5073455 and verifying they are properly applied, both everyday users and IT admins can reduce their exposure to newly patched vulnerabilities, fix nagging reliability bugs, and ensure their devices stay ready for future security transitions without last‑minute scrambling.