Microsoft shipped its optional May 2026 preview update for Windows 11 versions 24H2 and 25H2 on the 26th, and this release, KB5089573, is all about raw speed. If you’ve ever ground your teeth waiting for the Start menu to materialize or a pinned app to bounce into action, this patch aims to deliver measurable relief. The update introduces what Microsoft calls a “general performance improvement” that specifically targets latency in core shell surfaces—Start, Taskbar, and Search—as well as overall application launch times.

No new features or flashy UI changes accompany KB5089573. Instead, the focus is squarely on the underlying plumbing that governs how quickly Windows 11 responds to everyday interactions. Early reports from users who manually installed the preview indicate noticeable reductions in the milliseconds it takes for the Start menu to appear after pressing the Windows key, for search results to populate, and for applications to open from their icons.

What’s Actually Improved?

Microsoft’s support documentation for KB5089573 keeps it short: “This update improves the performance of Windows shell experiences and reduces the time it takes for apps to start.” Digging deeper, the improvements target the processes that handle the graphical shell. On a modern Windows 11 system, the Start menu, Taskbar, Action Center, and Search are all hosted by the ShellExperienceHost.exe process, while the Taskbar and system tray fall under explorer.exe. Both are critical to perceived system responsiveness.

When you click an app icon in the Taskbar or Start, the shell must communicate with the Windows Shell Interface and often wait for underlying services or disk I/O before the application window appears. KB5089573 apparently optimizes these code paths to reduce handshaking delays. The update may also prefetch certain dependencies or adjust thread priorities so that user-facing shell operations get faster access to CPU cycles, even when the system is moderately busy.

How the Low-Latency Profile Works

Under the hood, the update appears to tweak the system’s thread scheduling and resource allocation for shell components, effectively granting them a low-latency profile that ensures UI operations jump the queue when the system is under load. This concept isn’t entirely new—Microsoft has experimented with foreground boosting and priority scheduling in past feature updates—but KB5089573 seems to refine these techniques specifically for the Start, Search, and Taskbar surfaces.

The low-latency designation means that when a user presses the Windows key or clicks the Taskbar, the shell process temporarily gets a higher scheduling priority. That can slash input-to-response latency by double-digit percentages, making the interface feel significantly snappier. This is particularly impactful on older hardware or systems running many background processes, where GPU and CPU contention often delay UI rendering.

Application Launch Acceleration

Beyond the shell, KB5089573 also addresses the time between double-clicking an app and seeing its window appear. Windows 11 already benefits from technologies like Startup Boost for Microsoft Edge and revamped UWP/win32 launch pathways, but third-party apps haven’t always enjoyed the same speed. The update likely optimizes how the Windows NT loader resolves dependencies and maps executable files into memory. In practice, heavy applications like Visual Studio or Photoshop may still take a few seconds to load, but lightweight utilities and even built-in apps like Settings should pop open noticeably faster.

For applications pinned to the Taskbar or Start, the improved shell response combines with the loader optimizations to create a smoother end-to-end flow. The result: fewer moments of staring at a spinning cursor before an app becomes interactive.

Which Versions Get the Update?

KB5089573 is a preview update, meaning it rolls out as an optional cumulative update for Windows 11 builds. It targets two release channels:

  • Windows 11 version 24H2 (OS Build 26100.xxxx)
  • Windows 11 version 25H2 (OS Build 26200.xxxx)

The dual targeting suggests that Microsoft is aligning improvement efforts across the current generally available release and the next feature update, which will likely reach broad deployment later in 2026. Preview updates are opt-in: you must manually check for them under Settings > Windows Update > Advanced options > Optional updates. If you don’t install KB5089573 now, its fixes will be included in the mandatory June 2026 Patch Tuesday update.

A Growing Trend of Performance-First Patches

Microsoft has increasingly used its monthly “C” and “D” week preview updates to deliver performance boosts without waiting for a full feature drop. In late 2024 and early 2025, similar patches improved File Explorer loading times and reduced memory leaks in the Start menu. Windows 11 24H2 itself brought core changes like the new Rust-based kernel components and an optimized TCP/IP stack, but post-release tuning through cumulative updates remains essential.

KB5089573 continues this pattern. It doesn’t alter any APIs or deprecate features; it simply makes existing code run faster. That approach minimizes the risk of regressions while delivering immediate quality-of-life benefits. Enterprise IT departments, in particular, appreciate performance patches because they can validate them in staging environments before widespread deployment.

Real-World Impact and Early Feedback

Although the update has only been available for a short time, early adopters on insiders channels and tech forums are reporting consistent improvements. One user noted that the Search box now delivers results as soon as the first character is typed, whereas previously there was a half-second lag. Another measured a 40% reduction in cold-start time for a legacy inventory application that previously took over 8 seconds to initialize.

Such gains can accumulate meaningful productivity boosts over the course of a workday. For power users who rely on the Taskbar and Start dozens of times per hour, even a 100ms improvement per interaction adds up quickly. And on tablets or touchscreen devices where the Start screen is a primary launching pad, the latency reduction makes the system feel more fluid and responsive to gestures.

No Known Issues—Yet

As of the update’s release, Microsoft’s known issues list for KB5089573 is blank. That’s good news, but it’s early. Previous preview updates occasionally surfaced problems with specific printer drivers or VPN clients, but so far no such reports have emerged. Users with specialized software or customized shell extensions should still test the patch in a controlled manner before rolling it out broadly.

How to Get KB5089573 Right Now

To install the update, open Windows Update (Settings > Windows Update) and click “Check for updates.” If the preview is available for your device, you’ll see “2026-05 Cumulative Update Preview for Windows 11” with the KB number listed. Click Download and install, then restart when prompted. The download size is modest—typically under 300MB on most systems—and the installation takes only a few minutes on an SSD.

If you don’t see the update, confirm that your system meets the version requirements (24H2 or 25H2) and that you haven’t deferred optional updates via Group Policy. IT administrators managing Windows Update for Business can download the standalone MSU package from the Microsoft Update Catalog for bulk deployment.

Looking Ahead: June 2026 Patch Tuesday

For users who prefer stability over early access, all the performance tweaks in KB5089573 will be wrapped into the mandatory security update scheduled for June 9, 2026. That rollout will follow the typical staged deployment, reaching all compatible devices within a few days. The integration into a Patch Tuesday release also guarantees that Microsoft’s servers will handle the distribution load, minimizing download failures.

Beyond June, the 25H2 feature update is expected to incorporate these performance improvements natively, so fresh installations will benefit from the reduced latency right out of the box. Microsoft has not confirmed whether further performance patches are planned for later in the year, but given the positive reception of this type of update, it’s likely that additional tuning will continue.

Should You Install Now or Wait?

If you’re comfortable with preview updates and want to experience a snappier Windows 11 immediately, KB5089573 is a low-risk enhancement. Back up any critical data before installing—not because the update is known to cause issues, but because it’s always prudent when making system changes. The majority of users will appreciate the faster Start, Search, and app launch times, particularly on hardware that’s a couple of years old.

For those in enterprise environments or running mission-critical setups, waiting for the June Patch Tuesday release is the safer route. The fixes will be identical, and you’ll benefit from the additional week of real-world telemetry that Microsoft uses to flag any hidden regressions.

Ultimately, KB5089573 signals Microsoft’s commitment to sweating the small stuff. In an era where operating systems are mature and flashy new features are rare, the difference between a good experience and a great one often comes down to these incremental performance wins. This update is a pure velocity shot for your daily workflow.