Microsoft has released cumulative update KB5121157 (Build 28020.2818) for Windows 11 version 26H1, intended for insiders on the Beta channel. The update includes a small set of general improvements and fixes designed to improve system performance. The changes are being rolled out to insiders gradually, so they will not appear for everyone at the same time.
- Print management. The updated print management interface has been temporarily removed from insider builds — Microsoft is refining it based on feedback. The previous print management tools remain in place and work as before. The company plans to bring back the new version of the interface in one of the future builds.
- File Explorer. The File Explorer home page remembers the state of sections — whether they are expanded or collapsed — and opens in the same state in which it was left.
- Magnifier. The Magnifier toolbar has received an updated design: icons are aligned with the Windows 11 style, and padding and spacing have been adjusted. The behavior of the tool has not changed — viewing modes, zoom control, keyboard shortcuts, and read aloud work as before.
- Personalization — Background. The stability of the Settings > Personalization > Background page has been improved. Support for DIB images as desktop wallpapers has been added. Desktop slideshow now works more reliably on newly created accounts. Thumbnail resolution when selecting a background in Personalization > Background has been improved. The display of wallpaper preview in Settings on portrait-oriented monitors has been fixed. The stability of wallpaper change processing has been improved when it happens several times in a row. Slideshow now works with multiple desktops: the system no longer switches the background back to a single image. A bug from the previous build has been fixed where wallpapers turned black for some insiders after every reboot.
- Windows Recovery Environment. The Windows Recovery Environment (WinRE) can now connect to Wi-Fi profiles saved in the system, including supported networks with certificate-based authentication. Previously, it could only connect on its own to a wired network without authorization or to a Wi-Fi access point pre-configured separately for WinRE, and for other WPA2 and WPA3 networks the password had to be entered manually. Now, if the recovery scenario requires internet, the environment will use the data from an already saved profile. This applies to quick machine recovery and cloud system rebuild: neither the user nor the administrator will need to pre-enter Wi-Fi credentials in WinRE.
To install update KB5121157, go to Settings > Windows Update and click Check for updates. A computer restart will be required to complete the installation.
| Feature / Change | Performance Increase / Decrease | Optimization | PC Speed | Gaming Optimization |
|---|---|---|---|---|
| Print management interface temporarily removed | ⚪ No change | 🟡 Medium (rollback to previous tools) | ⚪ No change | ⚪ Not applicable |
| File Explorer remembers section states | 🟢 Slight improvement (faster navigation) | 🟢 High (UI state persistence) | 🟢 Slight improvement | ⚪ Not applicable |
| Magnifier toolbar design update | ⚪ No change | 🟡 Medium (cosmetic refinement) | ⚪ No change | ⚪ Not applicable |
| Personalization — Background stability and DIB support | 🟢 Slight improvement (fewer redraws) | 🟢 High (wallpaper processing) | 🟢 Slight improvement | 🟡 Low (less background churn during gaming) |
| Slideshow with multiple desktops | 🟢 Slight improvement | 🟢 High (multi-desktop handling) | 🟢 Slight improvement | 🟡 Low (less distraction, fewer resets) |
| WinRE saved Wi-Fi profiles | 🟢 Slight improvement (faster recovery) | 🟢 High (cloud rebuild connectivity) | 🟢 Slight improvement | ⚪ Not applicable |
Find and Change Settings
| Setting | Where to find | How to change |
|---|---|---|
| Print Management | Settings > Bluetooth & devices > Printers & scanners | The updated print management interface has been temporarily removed from insider builds. The previous print management tools remain in place and work as before. No action is required; Microsoft will bring back the new version in a future build. |
| File Explorer Home Section State | File Explorer > Home | The Home page now remembers whether sections are expanded or collapsed and opens in the same state in which it was left. Expand or collapse sections manually; the state will be saved automatically. |
| Magnifier Toolbar | Settings > Accessibility > Magnifier | The Magnifier toolbar has an updated design with icons aligned to the Windows 11 style and adjusted padding and spacing. Behavior is unchanged. To enable or disable Magnifier, go to Settings > Accessibility > Magnifier and turn the option on or off. |
| Personalization — Background | Settings > Personalization > Background | Support for DIB images as desktop wallpapers has been added. To change the background, open Settings > Personalization > Background, choose Picture or Slideshow, and select your image or folder. Slideshow now works with multiple desktops and on newly created accounts. No additional configuration is required. |
| Windows Recovery Environment Wi-Fi | Settings > Network & internet > Wi-Fi (saved profiles) | WinRE can now use saved Wi-Fi profiles, including certificate-based networks, without re-entering credentials. Save a Wi-Fi profile in Windows normally via Settings > Network & internet > Wi-Fi. No separate configuration in WinRE is needed. |
Official announcement on the Microsoft website.
The last 10 Windows updates:
| Update | Build | Version | Windows | Channel | Date |
|---|---|---|---|---|---|
| KB5121157 | 28020.2818 | 26H1 | Windows 11 | Beta | 2026-08-31 |
| KB5121158 | 28120.2824 | 26H1 | Windows 11 | Experimental | 2026-08-31 |
| KB5121794 | 26300.9278 | 26H2 | Windows 11 | Preview | 2026-08-27 |
| KB5121132 | 28120.2760 | 26H1 | Windows 11 | Experimental | 2026-08-21 |
| KB5124040 | 26220.9223 | 25H2 | Windows 11 | Beta | 2026-08-21 |
| KB5124042 | 26340.9233 | 26H2 | Windows 11 | Experimental | 2026-08-21 |
| KB5121106 | 28020.2731 | 26H1 | Windows 11 | Beta | 2026-08-17 |
| KB5121109 | 28120.2738 | 26H1 | Windows 11 | Experimental | 2026-08-17 |
| KB5124036 | 26220.9202 | 25H2 | Windows 11 | Beta | 2026-08-17 |
| KB5124038 | 26340.9212 | 26H2 | Windows 11 | Experimental | 2026-08-17 |