April 16, 2025—KB5059087 (OS Build 26100.3781) Out-of-band
Applies To
Windows Server 2025, all editionsRelease Date:
4/16/2025
Version:
OS Build 26100.3781
For information about Windows update terminology, see types of Windows updates and the monthly quality update types. To find an overview of Windows Server 2025, see its update history page.
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Improvements
This non-security update includes quality improvements. When you install this KB:
This update fixes an issue caused by 2025.04 B container images released on April 8, 2025 where Windows containers running in Hyper-V isolation mode could fail to start in some cases if their update level didn’t match that of the hosting utility virtual machine (UVM). The mismatch caused compatibility problems between system files, leading to startup failures. With this update, containers now correctly access the necessary system files from the host, improving reliability and compatibility across different Windows versions.
Windows Server 2025 servicing stack update (KB5058538)- 26100.3764
This update makes quality improvements to the servicing stack, which is the component that installs Windows updates. Servicing stack updates (SSU) ensure that you have a robust and reliable servicing stack so that your devices can receive and install Microsoft updates. To learn more about SSUs, see Simplifying on-premises deployment of servicing stack updates.
Known issues in this update
IT Admins
Devices that have certain Citrix components installed might be unable to complete installation of the January 2025 Windows security update. This issue was observed on devices with Citrix Session Recording Agent (SRA) version 2411. The 2411 version of this application was released in December 2024. Affected devices might initially download and apply the January 2025 Windows security update correctly, such as via the Windows Update page in Settings. However, when restarting the device to complete the update installation, an error message with text similar to “Something didn’t go as planned. No need to worry – undoing changes” appears. The device will then revert to the Windows updates previously present on the device. This issue likely affects a limited number of organizations as version 2411 of the SRA application is a new version. Home users are not expected to be affected by this issue.
Citrix has documented this issue, including a workaround, which can be performed prior to installing the January 2025 Windows security update. For details, see Citrix’s documentation.
Microsoft is working with Citrix to address this issue and will update this documentation once a resolution is available.
All users.
After installing the February 2025 Security update (KB5051987), released February 11, 2025, and later updates, on Windows Server 2025 devices, you might experience Remote Desktop sessions freezing shortly after connection. When this issue occurs, mouse and keyboard input become unresponsive within the session, requiring users to disconnect and reconnect
The resolution for this issue will be available in a future Windows update for Windows Server 2025.
All users.
After installing this update, you might face issues with the Azure Arc Setup wizard application. You might notice that the Azure Arc Setup wizard app stops responding when you are trying to launch it from either the Windows Start menu or the Taskbar. Resulting from this issue, the application event log in Event viewer might show an application error with Event ID:1000 indicating ‘Faulting application name’ as ‘AzureArcSetup.exe, version: 1.0.0.0’ along with an ‘Exception code’.
This issue was resolved by Windows updates released April 8, 2025 (KB5055523), and later. To keep your device performing at its best, make sure you have the latest update for your device. It contains important improvements and issue resolutions.
How to get this update
Before you install this update
Microsoft combines the latest servicing stack update (SSU) for your operating system with the latest cumulative update (LCU). For general information about SSUs, see Servicing stack updates and Servicing Stack Updates (SSU): Frequently Asked Questions.
Install this update
To install this update, use one of the following Windows and Microsoft release channels.
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Before you install this update To get the standalone package(s) for this update, go to the Microsoft Update Catalog website. This KB contains one or more MSU files that must be installed in order. Install this update Method 1: Install all MSU files together Download all MSU files for KB5055523 from Microsoft Update Catalog and place them in the same folder (for example, C:/Packages). Use Deployment Image Servicing and Management (DISM.exe) to install the target update. DISM will use the folder specified in PackagePath to discover and install one or more prerequisite MSU files as needed. Updating Windows PC To apply this update to a running Windows PC, run the following command from an elevated Command Prompt:
Or, run the following command from an elevated Windows PowerShell prompt:
Updating Windows Installation media To apply this update to Windows Installation media, see Update Windows installation media with Dynamic Update. To add this update to a mounted image, run the following command from an elevated Command Prompt:
Or, run the following command from an elevated Windows PowerShell prompt:
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If you want to remove the LCU
To remove the LCU after installing the combined SSU and LCU package, use the DISM/Remove-Package command line option with the LCU package name as the argument. You can find the package name by using this command: DISM /online /get-packages.
Running Windows Update Standalone Installer (wusa.exe) with the /uninstall switch on the combined package will not work because the combined package contains the SSU. You cannot remove the SSU from the system after installation.
File information
For a list of the files that are provided in this update, download the file information for cumulative update 5059087.
For a list of the files that are provided in the servicing stack update, download the file information for the SSU (KB5058538) - version 26100.33764.
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