Windows 10 KB5099539 Update (July 2026): New Features, Security Fixes & Improvements

Windows 10 users enrolled in Microsoft’s Extended Security Updates (ESU) program are now receiving the July 2026 cumulative update KB5099539. Released as part of Microsoft’s July 2026 Patch Tuesday rollout, Windows 10 KB5099539 addresses 570 vulnerabilities, including two exploited and one publicly disclosed zero-day flaw, and updates Windows 10 version 22H2 to build 19045.7548 and version 21H2 to build 19044.7548.

Although Windows 10 reached end of support in October 2025, Microsoft continues to deliver monthly security updates and quality improvements through the ESU program. KB5099539 focuses on fixing several known issues, improving Secure Boot deployment, strengthening networking and Remote Desktop security, and enhancing overall system reliability.

Windows 10 KB5099539 at a Glance

Item	Details
Update	KB5099539
Release Date	July 14, 2026
OS Build	19045.7548 (22H2), 19044.7548 (21H2)
Update Type	Cumulative Security Update
Available For	Windows 10 22H2 & 21H2 (ESU)
Release Channel	Patch Tuesday

What’s New in Windows 10 KB5099539?

While this update doesn’t introduce new features, it delivers several important reliability improvements, security enhancements, and fixes for known issues affecting Windows 10 devices.

Highlights include:

• OLE Automation repair for applications affected by the June 2026 update.
• File Explorer fix restoring the OneDrive shortcut when running as Administrator.
• Recycle Bin confirmation dialog now displays the correct file name.
• Network security hardening through TDI transport registration enforcement.
• Remote Desktop security improvements with SHA-2 certificate thumbprint support.
• Secure Boot status reporting and expanded certificate deployment.
• Updated keyboard hotkey cleanup behavior to improve system reliability.

1. Fixes Compatibility Issues in Some Applications

Microsoft has fixed a compatibility issue that started after installing the June 2026 security update that affected certain legacy and business applications. The problem involved OLE Automation (oleaut32.dll), which caused automation call failures and other compatibility issues in some software. KB5099539 resolves the issue and restores normal application behavior for affected apps.

2. OneDrive Shortcut Works Again in File Explorer

Windows 10 KB5099539 fixes a known issue where the OneDrive shortcut in File Explorer stopped working when File Explorer was launched with administrator privileges. If you frequently run File Explorer as Administrator, the OneDrive shortcut should now work normally again after installing this update.

3. Recycle Bin Displays the Correct File Name

Microsoft has fixed a small usability issue affecting the Recycle Bin. Previously, the confirmation dialog for permanently deleting a file could display an internal Recycle Bin filename instead of the original file name. After installing KB5099539, Windows once again shows the correct file name, making it easier to verify the file you’re deleting.

4. Improved Keyboard Shortcut Reliability

This update changes how Windows unregisters and cleans up keyboard hotkeys to improve system reliability. In rare cases, some built-in Windows features may temporarily stop responding to certain keyboard shortcuts after the update. Microsoft says restarting the affected application usually restores normal functionality.

5. Secure Boot Improvements Continue

Microsoft continues expanding the rollout of updated Secure Boot certificates ahead of the expiration of older certificates issued in 2011. KB5099539 adds dynamic Secure Boot status reporting in the Windows Security app and expands automatic certificate deployment to more supported consumer and unmanaged business devices, helping ensure systems continue to boot securely.

6. Networking Security Hardening

KB5099539 introduces an important networking security enhancement by enforcing TDI (Transport Driver Interface) transport registration requirements. Most home users won’t notice any changes, but applications that rely on unregistered third-party TDI transports may stop working after installing the update. Applications using properly registered transports are unaffected.

7. Remote Desktop (RDP) Security Enhancements

Microsoft has strengthened Remote Desktop security by adding support for SHA-2 certificate thumbprints for trusted RDP publishers while keeping SHA-1 support only for backward compatibility. The company also introduced new Group Policy guidance to help organizations control which .RDP files users can open and recommends migrating to SHA-256 certificate thumbprints before SHA-1 support is removed in a future release.

8. July 2026 Security Updates

As part of July 2026 Patch Tuesday, KB5099539 includes Microsoft’s latest security updates, addressing 570 vulnerabilities across Windows, Microsoft Office, SharePoint, .NET, Visual Studio, and other Microsoft products.

The update also fixes three important zero-day vulnerabilities, including two actively exploited flaws and one publicly disclosed vulnerability:

• CVE-2026-56155 – An elevation of privilege vulnerability in Active Directory Federation Services (AD FS).
• CVE-2026-56164 – An elevation of privilege vulnerability affecting Microsoft SharePoint Server.
• CVE-2026-50661 – A Windows BitLocker security feature bypass that could allow attackers with physical access to access encrypted data.

Microsoft recommends installing KB5099539 as soon as possible to receive the latest security protections, reliability improvements, and bug fixes.

Known Issues

At the time of writing, Microsoft has not reported any widespread new issues specifically introduced by KB5099539. Users should continue to monitor Microsoft’s release health dashboard for any emerging problems after installation.

How to install Windows 10 KB5099539

The update is available to devices enrolled in the ESU program, which has been extended through October 12, 2027, as well as Windows 10 Enterprise LTSC 2021 and IoT Enterprise LTSC 2021 systems. 

To install it manually, follow these steps:

1. Open Settings by pressing Windows + I.
2. Go to Update & Security > Windows Update.
3. Click Check for updates.
4. If the update is available, you’ll see 2026-07 Cumulative Update for Windows 10 Version 22H2 (KB5099539).
5. Click Download and install, then wait for Windows to complete the installation.
6. Restart your PC when prompted to apply the update.

Ensure your device is connected to a stable internet connection to download update files from the Microsoft server. Once done, reboot your computer to apply the changes.

Alternatively, you can download the standalone installer directly from the Microsoft Update Catalog by searching for “KB5099539.”

Windows 10 KB5099539 Direct download links 64-bit and 32-bit (x86).

• Locate the patch next to the correct edition and version of the operating system.
• To install the update, simply run the downloaded MSU file and Windows will automatically install the cumulative update.
• If you are looking for the latest Windows 10 version 22H2 ISO, click here.
• In addition, you can download the latest Windows 11 ISO images here.

How to Uninstall Windows 10 KB5099539

If installing KB5099539 causes issues on your device, you can uninstall the update to revert the changes.

Uninstall KB5099539 using the Windows Update History tool

1. Go to Windows Settings (Windows key + I) > Update & Security > Windows Update.
2. From the right-hand pane, click on View Update History.
3. Now, click on Uninstall updates.
4. Select Update for Microsoft Windows (KB5099539) and press the Uninstall button.

Uninstall KB5099539 using the command line

Another quick way to uninstall this update is by using the command prompt. Here are the commands:

1. Open the Command Prompt (Run > cmd)
2. Run the following command:
   
   wmic qfe list brief /format:table
3. This will show all the updates installed on the computer. Make sure KB5099539 is on the list.
4. To uninstall the update, run the following command
   
   wusa /uninstall /kb:5099539

The system needs to be restarted after uninstalling the update.

In addition, Microsoft has noted that Windows 10 version 21H2 reached end of service, meaning devices no longer receive monthly security and quality updates that protect against the latest security threats. Microsoft recommends installing the latest version 22H2 or Upgrade to Windows 11

How to Fix Windows 10 KB5099539 Installation Problems

If KB5099539 fails to install or causes issues after installation, try these troubleshooting steps:

• Run the Windows Update Troubleshooter – Go to Settings > Update & Security > Troubleshoot > Additional troubleshooters > Windows Update, then run the troubleshooter and apply any recommended fixes.
• Check Your Internet Connection – Ensure your internet connection is stable, restart your router if needed, and temporarily disable any VPN or proxy before trying the update again.
• Clear the Windows Update Cache – Stop the Windows Update service, delete the contents of C:\Windows\SoftwareDistribution\Download, restart the service, and then check for updates again.
• Repair Corrupted System Files – Open Command Prompt as Administrator and run sfc /scannow followed by DISM /Online /Cleanup-Image /RestoreHealth. Restart your PC after the scans finish.
• Update Device Drivers – Install the latest graphics, network, and chipset drivers from your PC or hardware manufacturer’s website to avoid compatibility issues during the update.
• Restart Your Computer – If the update appears stuck or a feature isn’t working correctly after installation, restart your PC and check for updates again. Many temporary update issues are resolved with a simple reboot.

Frequently Asked Questions

Also read:

• Difference Between Windows 10 Feature Updates and Cumulative Updates 
• Windows Update won’t download or fails to install on Windows 10 (Solved)
• How to Share Files and Printers Between Two Windows 10 Computers
• Windows 10 keeps shutting down and restarting automatically. Try these solutions
• Complete Review of Microsoft Windows 10 Operating System