Microsoft's September 2025 cumulative update for Windows 11 24H2 (KB5065426, build 26100.6584) landed with a mix of visible UI refinements, long‑awaited fixes, and a fresh wave of hardware‑gated AI features. But the most operationally consequential part of the release isn't anything you'll see on your desktop—it's the download size. The offline installer balloons to roughly 3.8 GB per architecture, nearly double a typical monthly patch, because Microsoft bundled on‑device Copilot AI model binaries directly into the package. That means every PC, whether it has a neural processing unit (NPU) to run those models or not, gets saddled with multi‑gigabyte payloads that serve no purpose on non‑Copilot+ hardware.

The update, part of the 24H2 servicing stream (with a parallel KB5065431 for 23H2 holdouts), demonstrates how aggressively Microsoft now pushes generative AI into Windows. While most headline features require a Copilot+ PC—a machine with a qualifying NPU, specific firmware, and cloud entitlement—the company ships model files universally, relying on server‑side flags and hardware checks to activate them later. The approach simplifies Microsoft's servicing pipeline but shifts bandwidth and storage costs onto end users and IT departments.

What’s actually new for users

Beyond the payload bulk, the September release delivers a handful of tangible improvements. Five changes stand out.

1. Recall gets a home page (Copilot+ only)

Recall, the controversial snapshot‑based activity history, now opens to a dedicated Home page that aggregates recent snapshots, frequently used apps, and top websites. A left‑side navigation rail provides quick access to Timeline, Feedback, and Settings. The feature remains strictly opt‑in, local, encrypted, and locked behind Windows Hello—a design Microsoft emphasizes after earlier privacy firestorms. For users who embrace Recall, the new landing page makes resuming tasks faster and more intuitive.

2. The “Agent in Settings” expands beyond ARM

Previously limited to Snapdragon X‑based Copilot+ devices, the on‑device AI assistant inside Settings (codenamed Settings Mu) now rolls out to systems with Intel and AMD processors, starting with English. The agent answers natural‑language queries (“how do I change my default printer?”) and can suggest settings changes, but always requires user confirmation. It runs entirely on the device, meaning no internet connection is needed for basic queries. Administrators can disable it via enterprise policy if desired.

3. Lock‑screen widgets become pick‑and‑choose

Widgets on the lock screen finally support granular customization. Instead of an all‑or‑nothing toggle, users can add, remove, and reorder individual widgets—weather, calendar, to‑do, traffic—to suit their preferences. The change brings welcome flexibility, especially for those who rejected the feature entirely because they couldn't control which information appeared.

4. Windows Search gains an image grid and indexing progress

Taskbar search now displays photos in a visual grid, making it easier to spot the right picture at a glance. Simultaneously, an indexing progress bar appears when the system is still cataloguing files, so users know whether search results are complete. Both are small quality‑of‑life boosts that reduce friction in everyday use.

5. Task Manager CPU reporting finally unified

For years, Task Manager’s Processes, Performance, and Users tabs could show different CPU usage percentages, confusing users and complicating third‑party tool comparisons. Microsoft has now standardized the metric across all views. Power users who relied on the old calculation can optionally add a “CPU Utility” column that preserves the legacy value. This fix—six months in the making—removes a long‑standing annoyance.

Other notable polish

Beyond the top five, the release includes a first‑run tutorial for the Click to Do overlay, a modernized Windows Hello sign‑in UI, an optional larger notification‑center clock with seconds, and more attention‑grabbing permission prompts that dim the background. These are incremental but collectively raise the overall fit and finish of Windows 11.

The real sting: a cumulative update packed with AI model binaries

While the features grab headlines, the update’s size is the hidden story. Independent reporting and catalog entries confirm that the 24H2 offline .msu installer weighs roughly 3.7–3.8 GB per architecture—far beyond a routine monthly patch. Microsoft is shipping on‑device Copilot model binaries inside the cumulative update. This ensures that Copilot+ features like Recall and the Settings agent can work offline with low latency on qualifying hardware. However, the “ship‑once, gate‑server‑side” strategy means every 24H2 machine downloads the full model payload, regardless of whether it has an NPU.

The practical consequences are immediate:
- Home users with small SSDs or metered connections face larger downloads and increased storage pressure. A 128 GB laptop can lose roughly 3% of its capacity to an update it can’t even use.
- IT administrators managing WSUS or manual deployment must plan for multi‑gigabyte artifacts, longer patch windows, and higher bandwidth consumption. Delivery Optimization peer‑to‑peer caching may help in large fleets, but the upfront hit remains.

A 23H2 update (KB5065431) does not include these model payloads, giving that build a temporary advantage in update size, but the long‑term trajectory is clear: Microsoft intends generative AI to be a first‑class component of Windows, delivered through servicing whether your hardware is ready or not.

Verification and cross‑checks

To ensure accuracy, the claims above were triangulated with multiple sources. Microsoft’s own Release Preview and Insider blog posts confirm the Agent in Settings expansion, the opt‑in nature of Recall, and the hardware/entitlement gating for Copilot+ experiences. Independent coverage from Windows Central and update‑tracking sites corroborates the visible UI changes (image grid search, lock‑screen widget customization, Task Manager fix) and the abnormally large .msu downloads attributed to bundled AI models. Community reports of forced Recall activation were traced to confusion about stubs and server flags; official documentation reiterates that Recall remains opt‑in and removable via standard Windows Features controls.

Practical guidance for users and IT admins

For home users

  • Don’t rush the preview patch: If you value disk space or bandwidth, wait for the automatic update arrival via Windows Update rather than manually downloading the full .msu. Windows Update will deliver only the differential bits, which are significantly smaller.
  • Check your hardware: Without a Copilot+ PC (NPU at required TOPS), you won’t get AI features enabled, but you’ll still store the models. Allow Windows to manage the update.
  • Recall opt‑in: If Recall appears on your system and you don’t want it, follow Microsoft’s official disable/uninstall steps. Avoid copy‑past DISM commands from untrusted sources; verify feature names with DISM /Online /Get‑FeatureInfo first.

For enterprise administrators

  • Pilot with a representative fleet: Include both Copilot+ and traditional hardware to understand what actually activates. Staged enablement means two identical machines may show different UIs after the update.
  • Plan for larger payloads: Adjust WSUS caching, Delivery Optimization policies, and maintenance windows. The 3.8 GB per architecture will strain limited‑bandwidth branch offices.
  • Control AI features with policy: Use the documented enterprise policy options to disable the Settings agent, Recall, or other on‑device AI experiences before broad deployment if your organization’s privacy posture requires it.
  • Have rollback plans ready: Recent servicing history shows Microsoft sometimes issues Known Issue Rollbacks (KIRs) for post‑patch regressions. Ensure recovery images and communication plans are in place.

Balanced assessment

Strengths: The update delivers meaningful polish: clearer permission prompts, a unified Task Manager, customizable lock‑screen widgets, and better image search. For Copilot+ adopters, Recall’s home page and the cross‑architecture Settings agent add genuine productivity value, all while keeping sensitive data on‑device.

Risks: The distribution model forces every user to carry the weight of AI model files, raising equity concerns for low‑storage or low‑bandwidth households. Fragmented availability—where features appear or disappear based on server‑side flags—complicates support and erodes user confidence. And features like Recall, despite strong safeguards, will continue to attract scrutiny in regulated environments.

Where this fits in Microsoft’s roadmap

The September update is both tactical and strategic. Tactically, it tidies long‑running UI inconsistencies and gives power users the seconds‑display clock they’ve requested for years. Strategically, it hardens the servicing model that will carry Windows into an AI‑first era: deliver model payloads centrally, gate features by hardware and entitlement, and iterate continuously via the cloud. That approach accelerates feature parity across Intel, AMD, and Snapdragon, but it imposes a measurable operational cost. For organizations, the sensible path is not to block updates indefinitely but to adopt measured rollout cadences, verify activation in their fleet, and tune distribution to absorb the larger payloads. For home users, the advice is simple: let Windows Update handle the deployment, and be aware that the age of lightweight cumulative updates may be coming to an end as generative AI becomes a permanent fixture.

The September patch is not a revolution, but it is a signal—one that forces every Windows 11 device to carry the infrastructure for an AI‑powered future, whether that future has arrived for your hardware or not.