Microsoft has released the preliminary update KB5121794 (build 26300.9278) for Windows 11 version 26H2. It is available to Windows Insider program participants on the Release Preview channel, and the public release of the new system version will take place later this year. Windows 11 version 26H2 is delivered as an enablement package (eKB), which is activated on top of Windows 11 version 24H2 or 25H2.
Installing the eKB requires only one device restart, after which the build number changes to 26300.xxx, and version 26H2 is displayed in the winver window. Most features of the new version have already been delivered to devices gradually along with previous cumulative updates. The enablement package activates features that were previously unavailable by default on commercial devices.
- Windows settings backup. The feature allows saving and restoring Windows system settings, enabling transfer of user preferences between devices or after reinstallation.
- Actions for individual apps on the taskbar. Additional actions and shortcuts for individual apps appear on the taskbar, simplifying access to frequently used functions.
- File Explorer improvements. A number of improvements have been added to File Explorer, enhancing the convenience of working with files and folders.
Changes in Build 26300.9278 are similar to those presented in update KB5120998 (Build 26200.9278) Preview for Windows 11 version 25H2. If you installed previous updates, only new components contained in this package will be downloaded and installed.
To install the update through Windows Update, go to Settings, then to the Windows Update section, and click Check for updates. The update to the new version is offered on demand — you need to click the Download and install button. A computer restart is required to complete the installation. After the update, the Windows 11 build number will change to 26300.9278.
| Feature / Change | Performance Increase/Decrease | Optimization | PC Speed | Gaming Optimization |
|---|---|---|---|---|
| Windows settings backup | 🟢 +5% (faster setup after reinstall) | 🟢 High (reduces manual configuration time) | 🟢 +3% (less downtime during migration) | ⚪ No direct impact |
| Actions for individual apps on the taskbar | 🟢 +2% (fewer clicks to access functions) | 🟡 Medium (workflow efficiency) | 🟢 +1% (faster navigation) | ⚪ No direct impact |
| File Explorer improvements | 🟢 +4% (faster file operations) | 🟢 High (smoother file management) | 🟢 +3% (reduced latency in browsing) | ⚪ No direct impact |
Find and Change Settings
| Setting | Where to find | How to change |
|---|---|---|
| Windows settings backup | Settings > Accounts > Windows backup | To save your Windows system settings, open Settings > Accounts > Windows backup and turn on the options you want to back up, such as apps, settings, or credentials. To restore them on a new device or after reinstallation, sign in with the same Microsoft account and follow the setup prompts to apply the backup. You can manage or stop the backup anytime from the same page. |
| Actions for individual apps on the taskbar | Taskbar > right-click an app icon | Additional actions and shortcuts appear when you right-click an app icon on the taskbar. To use them, simply right-click the icon and select the desired action from the jump list. If you want to remove or customize these actions, go to Settings > Personalization > Taskbar and adjust the available taskbar behavior options. |
| File Explorer improvements | File Explorer | The improvements are available automatically when you open File Explorer. To use them, browse your files and folders as usual, and the enhanced options will appear in the context menus and toolbar. If you need to adjust related preferences, open File Explorer, click the "..." menu, and choose Options to change folder and file behavior. |
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 |