Windows Server 2025 Insider Build 26280 has a new Sept. 15, 2025 expiration date

Microsoft has released the latest Windows Server build for members of the Windows Server Insider Program. The new build number is 26280. Keep in mind that this and future Windows Server Insider builds now have the Windows Server 2025 branding.

The big change in this build is a new expiration date of Sept. 15, 2025. Previously, the Windows Server Insider builds had a Sept. 15, 2024 expiration date. That means everyone who has downloaded and used any older versions of the Windows Server Insider needs to download and install the new 26280 build in order to keep using it after Sept. 15, 2024.

Here is the changelog;

What's New

Windows Admin Center (WAC)

Beginning with build 26252, Windows Server 2025 preview customers can download and install Windows Admin Center right from the Windows Server Desktop using the in-OS app that takes care of downloading and guides you through the installation process.

Note: You must be running a desktop version of Windows Server 2025 Datacenter or Standard preview to access this feature.

Windows Server Flighting is here!!

If you signed up for Server Flighting, you should receive this new build automatically later today. For more information, see Welcome to Windows Insider flighting on Windows Server - Microsoft Community Hub

The new Feedback Hub app is now available for Server Desktop users! The app should automatically update with the latest version, but if it does not, simply Check for updates in the app’s settings tab.

Known Issues

[NEW] Sysprep unable to generalize images. There is a known issue in build 26280.5000 that prevents images from being generalized via sysprep. The issue is understood and will be fixed in a future release.

Flighting: The label for this flight may incorrectly reference Windows 11. However, when selected, the package installed is the Windows Server update. Please ignore the label and proceed with installing your flight. This issue will be addressed in a future release.

WinPE - Powershell Scripts: Applying the WinPE-Powershell optional component does not properly install Powershell in WinPE. As a result, Powershell cmdlets will fail. Customers who are dependent on Powershell in WinPE should not use this build.

If you are validating upgrades from Windows Server 2019 or 2022, we do not recommend that you use this build as intermittent upgrade failures have been identified for this build.

This build has an issue where archiving eventlogs with "wevetutil al" command causes the Windows Event Log service to crash, and the archive operation to fail. The service must be restarted by executing "Start-Service EventLog" from an administrative command line prompt.

If you have Secure Launch/DRTM code path enabled, we do not recommend that you install this build.

Available Downloads

Downloads to certain countries may not be available. See Microsoft suspends new sales in Russia - Microsoft On the Issues.

Windows Server Long-Term Servicing Channel Preview in ISO format in 18 languages, and in VHDX format in English only.

Windows Server Datacenter Azure Edition Preview in ISO and VHDX format, English only.

Microsoft Server Languages and Optional Features Preview

Keys: Keys are valid for preview builds only

Server Standard: MFY9F-XBN2F-TYFMP-CCV49-RMYVH

Datacenter: 2KNJJ-33Y9H-2GXGX-KMQWH-G6H67

Azure Edition does not accept a key

Symbols: Available on the public symbol server – see Using the Microsoft Symbol Server.

Expiration: This Windows Server Preview will expire September 15, 2025.