Microsoft fixes Windows Server 2016 security update failures
Microsoft has resolved a known issue causing the June 2026 security updates to fail on Windows Server 2016 systems that were not fully up to date.
Microsoft has fixed a known issue that prevented the June 2026 security updates from installing on Windows Server 2016 systems that were not fully up to date. The bug, which caused error codes 0x80070002 or FILE_NOT_FOUND, primarily affected customers attempting to install the KB5094122 update without first installing last month's KB5087537 security update. The problem was acknowledged in an admin portal service alert after IT administrators reported widespread installation failures.
The issue stemmed from a servicing stack problem that blocked the cumulative update from installing correctly. Servicing stack updates are critical because they ensure the Windows Update infrastructure itself is healthy and can properly handle the installation of subsequent security patches. Without the prerequisite servicing stack update (KB5087537), the June 2026 security update could not complete, leaving systems exposed to unpatched vulnerabilities.
Microsoft has now resolved the installation failure issue, and affected devices should no longer experience errors when deploying the June 2026 KB5094122 security update. The company noted in its advisory: "Microsoft received reports that the June 2026 security update (the Originating KBs listed above) might fail to install on some devices running Windows Server 2016. Affected devices might have received error code 0x80070002 (ERROR_FILE_NOT_FOUND) during installation of the update."
This is not the first time Microsoft has had to address Windows update installation failures in recent weeks. Last month, Microsoft resolved a similar issue causing 0x800f0922 errors when deploying the May 2026 Windows 11 security update (KB5089549), which was triggered by insufficient free space on the EFI System Partition (ESP). In early June, Microsoft also warned customers about 0x80073712 or 0x800f0993 errors on some Windows devices upgraded to Windows 11 24H2 or 25H2.
Additionally, last week Microsoft fixed a known issue that caused Windows Server 2025 devices to boot into BitLocker recovery after installing the April 2026 security update, and a bug that triggered installation failures for Windows updates released since May 2025 when installed using the Windows Update Standalone Installer (WUSA). On Wednesday, Microsoft also confirmed that it is investigating an issue that blocks third-party applications from launching Word, Excel, PowerPoint, Access, and other Office applications on Windows systems after installing the June 2026 updates.
Administrators running Windows Server 2016 should ensure they apply the corrected update to protect their environments. The fix underscores the importance of keeping servicing stack updates current, as they are a prerequisite for successful security patch installation. Microsoft continues to recommend that customers install all available updates in the correct order to avoid these types of failures.