Microsoft has released cumulative update KB5120249 for Windows 10, version 22H2 as part of Patch Tuesday (August 2026) for devices enrolled in the Extended Security Updates (ESU) program.
- Secure Boot. New data has been added to more accurately identify target devices, which has increased the coverage of computers ready to automatically receive new Secure Boot certificates. In the coming months, their phased rollout via Windows Update will continue on supported PCs and unmanaged corporate devices.
- Backup. Fixed an error that caused automatic File History backup to network folders over the SMB protocol to fail with an Invalid Credentials error message. Due to this issue, scheduled backup did not save files.
To install the update, open the Settings menu, go to Update & Security and click Check for updates. The cumulative package KB5120249 will download and install automatically via Windows Update. A computer restart is required to complete the procedure.
| Feature / Change | Performance Increase or Decrease | Optimization | PC Speed | Gaming Optimization |
|---|---|---|---|---|
| Secure Boot – expanded device identification data for automatic certificate updates | ⚪ No direct impact | 🟢 Improved (broader automated certificate rollout reduces manual intervention) | ⚪ Negligible | ⚪ No impact |
| File History backup – fixed SMB credential error causing backup failures | ⚪ No direct impact | 🟢 High (backup reliability restored; scheduled copies saved correctly) | ⚪ Negligible | ⚪ No impact |
Find and Change Settings
| Setting | Where to find | How to change |
|---|---|---|
| Secure Boot Certificate Updates | Settings > Windows Update > Advanced options > Optional updates | Secure Boot certificates are delivered automatically via Windows Update. To check for and install available certificate updates, open Settings > Windows Update > Advanced options > Optional updates, and install any pending updates under the "Other updates" section. No manual configuration is required to receive the phased rollout. |
| File History Backup to Network (SMB) | Settings > Accounts > Windows Backup Control Panel > System and Security > File History |
To enable or disable automatic File History backup, go to Control Panel > System and Security > File History, select a network folder as the backup drive, and turn on File History. With the fix installed via Windows Update, scheduled backups to SMB network folders will no longer fail with an Invalid Credentials error. You can also manage backup preferences under Settings > Accounts > Windows Backup. |
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 |