If you manage Windows Server 2016 or Windows 10 version 1607 LTSB systems and saw KB5099542 listed as a major update in your patch management console on July 14, 2026, here is what you need to know.
KB5099542 is a Servicing Stack Update released July 14, 2026 for Windows 10 version 1607 Enterprise LTSB, Windows 10 IoT Enterprise LTSB 2016, and Windows Server 2016 across all editions. It is the prerequisite that must be installed before the July 2026 cumulative security update KB5099535 can install correctly — and it replaces the previously released servicing stack update KB5094141.
There is also a deadline worth flagging immediately: Microsoft will no longer provide free software updates from Windows Update, technical assistance, or security fixes for Windows 10 Enterprise LTSB 2016 after October 13, 2026. That is less than three months away from the July 2026 update cycle.
What Is KB5099542?
KB5099542 is a Servicing Stack Update released on July 14, 2026, for Windows 10 version 1607 Enterprise LTSB, Windows 10 IoT Enterprise LTSB 2016, and Windows Server 2016 across all editions. This update enhances the servicing stack component responsible for installing Windows updates, ensuring devices can reliably receive and install Microsoft patches. The update replaces the previously released KB5094141.
The servicing stack is the set of Windows components responsible for installing, updating, and removing updates. It is not the content of any particular update — it is the delivery mechanism itself. When Microsoft ships a Servicing Stack Update, it fixes bugs in the update infrastructure and ensures that future update packages can install correctly on target systems.
KB5099542 updates this infrastructure for Windows Server 2016 and Windows 10 1607 LTSB — ensuring these older but still widely deployed platforms can reliably receive the July 2026 security content and subsequent monthly patches through their remaining support window.
How KB5099542 Differs From Other July 2026 SSUs
This month’s update cycle included multiple Servicing Stack Updates for different Windows versions. Understanding how KB5099542 differs from the others clarifies why it appears as a separate item in your patch console.
KB5094135 — June 2026 SSU, bundled inside KB5094126. For Windows 11 25H2 and 24H2.
KB5120102 — July 2026 SSU, bundled inside KB5101650, KB5121767, and KB5121768. For Windows 11 25H2 and 24H2.
KB5099542 — July 2026 SSU, standalone and separate. For Windows 10 1607 LTSB and Windows Server 2016.
The key difference is delivery method. Modern Windows 11 servicing stack updates ship bundled inside their companion cumulative updates — users never see them as separate items. KB5099542 ships as a standalone update because Windows 10 1607 and Windows Server 2016 use the older update delivery model that predates the bundled SSU approach Microsoft introduced for newer Windows versions.
This means IT administrators managing these older systems must explicitly approve and deploy KB5099542 through their patch management tools, then approve KB5099535 as the follow-on cumulative update — in that specific order.
Why KB5099542 Must Be Installed Before KB5099535
For Windows Server 2016, the release includes the MAJOR Servicing Stack Update KB5099542 and the Cumulative Update KB5099535. These form the core of the July 2026 patch set for this version. The servicing stack update prepares the system for subsequent installations, while the cumulative update delivers the security fixes.
The installation order is not optional. Attempting to install KB5099535 on a system without KB5099542 in place will fail. The cumulative update package was built against the servicing stack version that KB5099542 delivers — without that baseline, the installer cannot complete the operation.
Well-configured automated patch management systems handle this ordering automatically. BigFix, for example, released both updates on July 14, 2026 with KB5099542 designated as a prerequisite that must complete before KB5099535 is attempted. WSUS and Configuration Manager administrators should verify their update dependencies are configured correctly to enforce this sequence.
The Companion Update — KB5099535
KB5099542 prepares the system. KB5099535 delivers the security content.
KB5099535 is the July 14, 2026 cumulative security update for Windows Server 2016, moving it to OS build 14393.9339. It is the vehicle for July 2026’s security patches on this platform — the same Patch Tuesday cycle that delivered KB5101650 to Windows 11 and KB5099539 to Windows 10 22H2 ESU users.
KB5099535 addresses a compatibility issue in OLE Automation that was introduced by the June 2026 security update — the same OLE Automation fix that shipped to Windows 10 and Windows 11 users through their respective July updates.
The July 2026 Patch Tuesday addressed a record number of vulnerabilities. Windows Server 2016 receives its portion of those fixes through KB5099535 — but only after KB5099542 has successfully prepared the servicing stack.
The Critical End of Support Deadline
For organizations still running Windows 10 Enterprise LTSB 2016, KB5099542 arrives with an important piece of timing context.
Microsoft will no longer provide free software updates from Windows Update, technical assistance, or security fixes for Windows 10 Enterprise LTSB 2016 after October 13, 2026.
October 13, 2026 is approximately three months from the July 2026 update cycle. KB5099542 and its companion KB5099535 are among the last handful of monthly updates these systems will receive before end of support.
What this means in practice:
After October 13, 2026, Windows 10 Enterprise LTSB 2016 systems receive no further security patches. Vulnerabilities discovered after that date remain unpatched indefinitely on those systems. Any internet-connected or network-accessible Windows 10 1607 LTSB system still running after October 2026 accumulates security debt with each passing month.
Windows Server 2016 is on a different timeline — it continues to receive support beyond October 2026. Administrators managing mixed environments with both Windows 10 1607 LTSB clients and Windows Server 2016 servers need to plan client migrations while maintaining server update cycles through their respective supported lifetimes.
Secure Boot Certificate Notice
Secure Boot certificates used by most Windows devices are set to expire starting in June 2026. Microsoft has been updating these certificates on consumer and non-managed business devices for the past months. Devices that have not received the newer certificates will continue to start and operate normally, and standard Windows updates will continue to install. We will continue to install the newer certificates via Windows updates in the coming months. IT administrators should follow the guidance on the Secure Boot Playbook for Windows clients and Windows Server.
This notice appears specifically in KB5099542’s documentation because Windows Server 2016 and Windows 10 1607 LTSB environments frequently include systems that have not received regular monthly updates — increasing the likelihood that some devices in these fleets have not yet received the updated Secure Boot certificates.
IT administrators managing these platforms should verify Secure Boot certificate status across their fleet, particularly on intermittently connected devices and systems rebuilt from older installation media that predate the certificate update rollout.
How to Install KB5099542
Correct installation order:
Step 1 — Install KB5099542 first.
Step 2 — Install KB5099535 after KB5099542 completes.
Do not attempt to install KB5099535 before KB5099542. The cumulative update will fail.
Method 1 — Windows Update (Managed Environments)
In environments where Windows Update is not blocked, KB5099542 will appear automatically. Install it, allow it to complete, then check for updates again to receive KB5099535.
Method 2 — WSUS
Approve KB5099542 in WSUS with a dependency or sequencing rule that ensures it deploys before KB5099535. Verify the product targeting is set for Windows Server 2016 and Windows 10 1607 LTSB as appropriate for your environment. Allow sufficient time for KB5099542 to deploy across your fleet before approving KB5099535.
Method 3 — BigFix and Patch Management Tools
BigFix released corresponding content on July 14, 2026 to facilitate automated deployment. For Windows Server 2016, the content release designates KB5099542 as MAJOR and prerequisite to KB5099535. Verify your BigFix baseline or Fixlet configuration enforces the correct installation sequence.
Method 4 — Microsoft Update Catalog (Manual)
Go to catalog.update.microsoft.com. Search for KB5099542. Download the x64 package for your target OS — Windows 10 version 1607 or Windows Server 2016. Run the downloaded .MSU file on the target system. After completion, search for and install KB5099535.
If you encounter error 0x80244022 during catalog access or download, our complete fix guide covers every solution including WSUS-specific resolutions.
Verifying KB5099542 Installed Correctly
After installing KB5099542, verify before proceeding to KB5099535.
Method 1 — Windows Update History
Go to Settings, Update and Security, Windows Update, View update history. KB5099542 should appear with a Successfully installed status dated July 14, 2026.
Method 2 — PowerShell
Open PowerShell as administrator and run:
powershell
Get-HotFix -Id KB5099542If installation details are returned, the SSU is present and the system is ready for KB5099535.
Method 3 — DISM
Open Command Prompt as administrator and run:
dism /online /get-packages | findstr KB5099542A result in the output confirms successful installation.
Can KB5099542 Be Uninstalled?
No. Like all Servicing Stack Updates, KB5099542 cannot be removed after installation. It becomes part of the Windows update infrastructure. Microsoft does not provide an uninstallation path for SSU components — this is standard policy across all Windows versions and all SSU packages, including KB5043080, KB5094135, and KB5120102.
The companion cumulative update KB5099535 can be uninstalled through the standard update removal process if needed. KB5099542 cannot.
KB5099542 in Context — The July 2026 Patch Landscape
The July 2026 Patch Tuesday was Microsoft’s largest ever — fixing a record number of vulnerabilities across all supported Windows versions simultaneously. KB5099542 is the Windows Server 2016 and Windows 10 1607 LTSB piece of that larger release.
For comparison, the same Patch Tuesday delivered:
KB5101650 — Windows 11 25H2 and 24H2. 570 vulnerabilities. Point-in-Time Restore. Bundled with KB5120102 SSU.
KB5099539 — Windows 10 22H2 ESU. 570 vulnerabilities. OLE Automation fix. RDP SHA-2 hardening.
KB5099542 + KB5099535 — Windows Server 2016 and Windows 10 1607 LTSB. The July security content for these older platforms, delivered through the pre-bundled SSU model that these versions still use.
The security priorities are the same across all platforms. The delivery mechanism differs based on which generation of Windows update infrastructure each version uses.
Frequently Asked Questions
What is KB5099542?
KB5099542 is a Servicing Stack Update released July 14, 2026 for Windows 10 version 1607 Enterprise LTSB, Windows 10 IoT Enterprise LTSB 2016, and Windows Server 2016. It enhances the servicing stack responsible for installing Windows updates and replaces the previous SSU KB5094141. It must be installed before the July 2026 cumulative update KB5099535.
Why must KB5099542 be installed before KB5099535?
KB5099535 — the July 2026 cumulative security update for Windows Server 2016 — requires the servicing stack version that KB5099542 delivers. Installing KB5099535 without KB5099542 in place will fail. IT administrators must configure their patch management tools to enforce this installation order.
What does KB5099542 replace?
KB5099542 replaces the previously released Servicing Stack Update KB5094141 for Windows 10 version 1607 and Windows Server 2016.
Can KB5099542 be uninstalled?
No. Servicing Stack Updates cannot be removed after installation. This is standard Microsoft policy for all SSU components across all Windows versions.
What is the end of support date for Windows 10 Enterprise LTSB 2016?
Windows 10 Enterprise LTSB 2016 reaches end of support on October 13, 2026. After that date, Microsoft will no longer provide security fixes, software updates, or technical assistance for this version.
Does KB5099542 apply to Windows 11 or Windows 10 22H2?
No. KB5099542 applies only to Windows 10 version 1607 Enterprise LTSB, Windows 10 IoT Enterprise LTSB 2016, and Windows Server 2016. Windows 11 received its July 2026 SSU as KB5120102 bundled inside KB5101650. Windows 10 22H2 ESU users received their July update through KB5099539.
What is the companion cumulative update for KB5099542?
KB5099535 is the July 14, 2026 cumulative security update for Windows Server 2016, moving it to OS build 14393.9339. KB5099542 must be installed first to prepare the servicing stack before KB5099535 can install.
How do I verify KB5099542 installed correctly?
Run Get-HotFix -Id KB5099542 in PowerShell as administrator. If installation details are returned, the SSU is present and the system is ready for KB5099535. You can also check Windows Update History or run DISM /online /get-packages and search for KB5099542 in the output.
