Windows 11 KB5077239 Preview: What the Windows 11 26H1 Update Brings
The latest preview, KB5077239, is now rolling out to Windows 11 PCs under a gradual “phased” schedule and will hit every device in a normal release later this month. The package packs a mix of new Copilot+ goodies, tighter File Explorer aesthetics, camera‑enhancement tweaks, and several accessibility improvements that feel more like incremental polish than a full‑blown overhaul.
Copilot+ Enhancements
Windows 11 has finally started treating the Copilot experience as more than just a splashy demo. The Settings Agent now understands German, Portuguese, Spanish, Korean, Japanese, Hindi, Italian, and Simplified Chinese, so users who switch languages on the fly get settings suggestions in their native tongue. One of the more useful changes is the new “Recommended settings” button that pops up inline when you tweak something recently modified—no need to scroll a dozen pages in Settings to find the toggle you just flipped.
File Explorer Tweaks
If you’ve ever complained about File Explorer’s dark mode looking like it was borrowed from an old Windows 10 theme, this update fixes that. Copy, move, delete dialogs, progress bars, and even chart views now match the system‑wide dark palette, making high‑contrast thumbnails easier to read on low‑light monitors. The context menu got a clean‑up too; Share, Copy, Move sit in a single, uncluttered pane regardless of whether you’re using a mouse or voice commands.
Camera & Studio Effects
The update now lets any connected camera—USB or rear laptop—enable Windows Studio Effects via Settings > Bluetooth & devices > Cameras. After turning it on, you can tweak background blur, lighting, and more right from the quick‑settings tile.
Voice & Accessibility Updates
Voice Typing got a small but practical tweak: the “Wait time before acting” slider lets users adjust how long Windows waits after speaking before executing a command. That helps folks who speak in a drawn‑out cadence that used to trigger misinterpretations. Narrator, too, now offers finer control over which on‑screen elements it announces, reducing redundant chatter for users with low vision.
Security and Sign‑In Improvements
Windows Hello Enhanced Sign‑in Security (ESS) is expanding beyond laptops. A peripheral fingerprint sensor can now be paired to a desktop or any Copilot+ PC, giving the same lock‑screen confidence without needing a built‑in reader. For those who use Windows 11 on an older device that only supports password sign‑ins, this adds an extra layer of protection.
Other Notable Fixes
- The “Lock screen” has been patched to stop the occasional freeze when you slide between backgrounds.
- Explorer.exe no longer stalls on first log‑in if a startup app is misbehaving—a bug that caused taskbars to disappear for some users.
- A memory leak in the slide‑show lock screen was caught, preventing long‑term performance hiccups.
The update also includes quality‑of‑life fixes for BitLocker recovery and Windows Sandbox stability. Most of these changes come pre‑bundled with the preview; you’ll only need to hit “Check for updates” in Settings > Windows Update to get them if your system is still on the older 26H1 build.
If you’re running a device that’s already part of the gradual rollout, expect new Copilot options and dark‑mode consistency over the next few weeks. Once the normal rollout kicks in, every eligible PC will receive the same set of improvements—no more waiting for your specific firmware or OEM to catch up.
February 24, 2026—KB5077239 (OS Build 28000.1643) Preview
February 24, 2026—KB5077239 (OS Build 28000.1643) Preview - Microsoft Support
