Microsoft has released cumulative update KB5121132 (Build 28120.2760) for Windows 11 version 26H1, intended for insiders on the Experimental channel. This update brings several notable improvements to File Explorer, Microsoft Store, and the input system, and also contains a fix for an issue with the mouse pointer not displaying in some applications.
- File Explorer. PDF files and other files, except HTML, downloaded from the internet now automatically appear in the preview pane.
- Microsoft Store. Added support for in-app purchases in packaged WinUI 3 applications that require elevation. Developers will be able to offer purchases through Microsoft's built-in commerce platform.
- Input. Fixed an issue introduced in recent builds where the mouse pointer did not appear in some applications.
- App compatibility. Due to a known compatibility issue with PUBG: BATTLEGROUNDS, the game may fail to launch after installing this build. The restriction is intentional to avoid stability issues while Microsoft works on a fix together with the game developer. The company promises to share details and a timeline later.
The update is installed through Windows Update: go to Settings > Windows Update and click Check for updates. A computer restart is required to complete the installation. This update is distributed only to Windows Insider Program participants on the Experimental channel and is not intended for regular users of the stable version of Windows 11.
| Feature / Change | Performance Increase or Decrease | Optimization | PC Speed Impact | Gaming Optimization |
|---|---|---|---|---|
| File Explorer preview pane now shows PDF and other non-HTML downloaded files | 🟡 Slight decrease possible (more background rendering) | 🟢 Improved file inspection without opening apps | ⚪ No measurable change | ⚪ Not applicable |
| Microsoft Store supports in-app purchases in elevated packaged WinUI 3 apps | ⚪ No direct impact | 🟢 Better for developers and commerce | ⚪ No change | ⚪ Not applicable |
| Fix: mouse pointer not appearing in some applications | 🟢 Slight increase (less UI lag or redraw issues) | 🟢 Improves usability and responsiveness | 🟢 Minor improvement in affected apps | 🟢 Minor improvement (better input feedback) |
| PUBG: BATTLEGROUNDS launch block due to known compatibility issue | 🔴 Temporary decrease for affected users | 🔴 Intentional restriction to avoid crashes | ⚪ No general PC speed change | 🔴 High negative impact (game may fail to launch) |
Official announcement on the Microsoft website.
The last 10 Windows updates:
| Update | Build | Version | Windows | Channel | Date |
|---|---|---|---|---|---|
| KB5127757 | 28120.3181 | 26H1 | Windows 11 | Experimental | 2026-10-07 |
| KB5127758 | 26220.9606 | 25H2 | Windows 11 | Beta | 2026-10-07 |
| KB5127754 | 28020.3172 | 26H1 | Windows 11 | Beta | 2026-10-07 |
| KB5127753 | 26340.9616 | 26H2 | Windows 11 | Experimental | 2026-10-07 |
| KB5124192 | 28120.3151 | 26H1 | Windows 11 | Experimental | 2026-10-02 |
| KB5124196 | 28020.3142 | 26H1 | Windows 11 | Beta | 2026-10-02 |
| KB5124197 | 26220.9587 | 25H2 | Windows 11 | Beta | 2026-10-02 |
| KB5124193 | 26340.9596 | 26H2 | Windows 11 | Experimental | 2026-10-02 |
| KB5124166 | 26220.9568 | 25H2 | Windows 11 | Beta | 2026-09-25 |
| KB5124163 | 28020.3112 | 26H1 | Windows 11 | Beta | 2026-09-25 |