Windows 10 KB5099539: July 2026 Patch Tuesday Update
Windows 10 KB5099539 is now rolling out as part of MS’s July 2026 Patch Tuesday for PCs enrolled in the Extended Security Updates (ESU) program. MS has also provided direct download links for KB5099539 offline installers (.msu). However, these installers will not function unless your device already has ESU activated.
Update Details
If you haven’t checked for updates yet, the patch is labeled as “2026-07 Cumulative Update for Windows 10 Version 22H2 for x64-based Systems (KB5099539).” Installing this update will upgrade the OS to Windows 10 Build 19045.7548, while Windows 10 Enterprise LTSC 2021 will move to Build 19044.7548.
Download Links for Windows 10 KB5099539
Direct download links for Windows 10 KB5099539 are available for 64-bit and ARM-64 systems through the MS Update Catalog. The offline installer (.msu) download size is approximately 1067MB. However, for most users, it is recommended to use Windows Update for a seamless experience. Offline installers are primarily useful for IT administrators managing multiple systems or when Windows Update encounters errors.
You can download and install the update by navigating to:
- Settings > Updates & Security > Windows Update
What’s New in Windows 10 Build 19045.7548?
This update incorporates all the relevant fixes from MS’s record-setting July 2026 Patch Tuesday for Windows 11 (KB5101650), which addressed 570 security vulnerabilities, including two zero-day exploits. Here are the key highlights:
Remote Desktop Improvements
MS has added support for SHA-2 certificate thumbprints for trusted RDP publishers. While SHA-1 support remains for backward compatibility, it is slated for removal in future updates. Administrators are encouraged to migrate to SHA-256 or stronger alternatives.
Additionally, new Group Policy guidance has been introduced to improve security for .rdp files, particularly to defend against phishing attacks using malicious .rdp files.
Security Hardening
The update enforces TDI (Transport Driver Interface) transport registration requirements. Applications using sockets over unregistered third-party TDI transports may cease functioning. Registered TDI transports are unaffected, but older networking or VPN software may encounter issues. MS has provided a support document for resolving these cases.
Bug Fixes
- Fixed a compatibility issue in oleaut32.dll that caused apps using
IDispatch::Invokewith BYREF parameters to fail. - Resolved a bug where the OneDrive shortcut in File Explorer failed when running in administrative mode.
- Fixed a Recycle Bin issue that displayed internal file names in deletion confirmation dialogs.
- Addressed issues with hotkey unregistering and cleanup, though rare cases may require restarting affected apps.
Secure Boot Updates
Secure Boot certificates, which started expiring in June 2026, are being replaced with updated 2023 certificates. This update enables dynamic status reporting for Secure Boot states in the Windows Security app. Devices that haven’t yet received the updated certificates will continue to start normally, and regular Windows updates will still install without issue.
To check your Secure Boot status, navigate to:
- Windows Security > Device Security > Secure Boot
OneDrive Sync App Support Changes
MS will end support for the OneDrive sync app on Windows 10 version 22H1 and earlier starting August 15, 2026. Devices on Windows 10 22H2 will receive updates until October 10, 2028. Older versions will lose feature updates, bug fixes, and security patches after these dates.
The app won’t stop working immediately, but functionality cannot be guaranteed. MS recommends upgrading to Windows 10 22H2 or Windows 11 for continued support.
Servicing Stack Update and Deployment
This cumulative update includes the latest Servicing Stack Update (SSU), KB5104021 (version 19041.7546), which improves update reliability. If deploying this update offline, ensure the following:
- For images without the July 2023 (KB5028244) or later LCU, install the standalone October 2023 SSU (KB5031539) first.
- For WSUS deployments or standalone installs, devices without the May 2021 (KB5003173) or later LCU require the standalone August 2021 SSU (KB5005260).
Known Issues
MS has confirmed there are no new known issues with this update. Given the large number of patched vulnerabilities, it is highly recommended to install this update promptly.
Windows 10 Extended Security Updates (ESU)
Windows 10 reached the end of support in October 2025. Without ESU, devices will no longer receive security updates, including KB5099539. Fortunately, MS has extended the consumer ESU program through October 12, 2027. Enrollment options include:
- Sync settings to a MS account for free ESU.
- Redeem 1,000 MS Rewards points or pay a $30 one-time fee for up to 10 devices.
To enroll, navigate to:
- Settings > Update & Security > Windows Update > Enroll now
Final Notes
Windows 10 continues to remain a popular choice for millions of users, with MS supporting it through features like WSL Containers. For those who have already transitioned to Windows 11, a major update (KB5101650) has been released as part of July 2026 Patch Tuesday. Check out our full coverage here.
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