Microsoft has released the Windows 10 KB5120249 cumulative update for versions 22H2 and 21H2 to fix security vulnerabilities and bugs.

Today's update is mandatory as it contains the August 2026 Patch Tuesday security updates.

You can install today's update by going to Start > Settings > Update & Security > Windows Update and clicking on 'Check for updates.'

You can also manually download and install the update from the Microsoft Update Catalog.

After installing today's update, Windows 10 will be updated to OS Builds 19045.7663 and 19044.7663.

What's new in the Windows 10 August 2026 Patch Tuesday update

With today's update, Microsoft is fixing a File History backup issue and expanding the rollout of new Secure Boot certificates.

Here's the full list of improvements and fixes:

• [Backup]File History automatic backups to network shares using Server Message Block (SMB) might fail with an incorrect "invalid credentials" error. When this issue occurs, scheduled backups do not copy any files. This update resolves the issue.
• [Secure Boot]This update includes additional high confidence device targeting data, increasing coverage of devices eligible to automatically receive new Secure Boot certificates. Certificate deployment via Windows updates continues across supported PCs and non-managed business devices in the coming months.

Microsoft is not aware of any new issues with this month's Patch Tuesday update, but we'll update the article if we come across major problems.

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