Windows 11 Update KB5079391 Fixes File Explorer and Smart App Control

Dealing with a sluggish File Explorer or annoying system restarts just to change security settings is a major pain point for PC users, but the new Windows 11 update KB5079391 aims to resolve these exact frustrations. Microsoft is finally delivering on its recent promises to improve system performance and customization by rolling out a series of targeted quality-of-life improvements. Last week, the company made headlines by committing to a better operating system experience, promising less invasive Copilot integration and enhanced overall responsiveness.

Less than a week later, the release of the 2026-03 Preview Update (KB5079391) (26200.8116) shows the tech giant is taking its first concrete steps toward fulfilling those promises. While the rollout is gradual, the update introduces several highly requested fixes that address underlying problems plaguing the platform for years. Instead of merely applying band-aids through third-party alternatives, Microsoft is directly modifying core system behaviors.

To take advantage of these new system-level enhancements, you need to ensure your machine is prepared for the gradual rollout. Here is how to access and utilize the latest additions.

• Verify your system is enrolled in the Windows Insider Preview program to receive early builds. This ensures you have access to the gradual rollout of OS Builds 26200.8116 and 26100.8116.
• Download the KB5079391 package via your system update settings. This enables the new security toggles and file management fixes on your machine.

1. Toggle Smart App Control (SAC) directly from your security settings without rebooting. This ensures you can quickly enable or disable app protections on the fly, eliminating the previously required system restart that interrupted workflows.
2. Whitelist trusted internet-downloaded files directly within File Explorer. This enables power users to bypass the annoying preview blocks introduced in previous updates, making file management significantly smoother.
3. Enable 1000Hz refresh rate support in your advanced display settings if you own compatible hardware. This ensures your operating system can fully utilize next-generation monitors, such as the recently showcased Acer 1000Hz display, for unprecedented visual fluidity.

While the Windows 11 update KB5079391 is a step in the right direction, it is clear that Microsoft is currently prioritizing niche power-user features over sweeping mainstream overhauls. The addition of 1000Hz refresh rate support is incredibly forward-looking, considering the brand Acer only recently showcased the first compatible monitor, but it will not impact the average user today. This shows Microsoft is future-proofing the OS for extreme gaming enthusiasts, even if the hardware market is just now catching up.

However, the ability to toggle Smart App Control without a restart and the streamlined whitelisting in File Explorer are critical quality-of-life fixes. These changes indicate that Microsoft is actually listening to the granular complaints of its user base rather than just pushing broad AI integrations. The File Explorer preview block for downloaded files has been a persistent annoyance, and fixing it proves the development team is looking at actual daily friction points.

If the company continues this momentum and addresses the deeper underlying performance issues within File Explorer, Windows 11 could finally shed its reputation as a clunky successor to Windows 10. For now, power users should install this preview build to take advantage of the immediate workflow improvements, while mainstream users can remain cautiously optimistic for future stable releases.