Insider New Windows Server 2025 LTSC Preview Build 26040 - Jan. 26

Hello Windows Server Insiders!

Today we are pleased to release a new build of the next Windows Server Long-Term Servicing Channel (LTSC) Preview that contains both the Desktop Experience and Server Core installation options for Datacenter and Standard editions, Annual Channel for Container Host and Azure Edition (for VM evaluation only). Branding has been updated for the upcoming release, Windows Server 2025 in this preview - when reporting issues please refer to Windows Server 2025 preview.

What's New​

Windows Server Flighting is here!!

[NEW] If you signed up for Server Flighting, you should receive this new build automatically later today (Friday, January 26, 2024).

Join Server Flighting

To set up flighting on Server (build 26010 or later), just navigate to Settings > Windows Update > Windows Insider Program to opt in your device. Flighting will only be available for the Canary Channel and flights for Server begin with build 26040. Our intention is to flight the same builds as client (desktop) for Server flights but the schedule in which we release Server flights might differ slightly (for example – Server releases bi-weekly). Flighting for Server applies to the Desktop Experience only.



The following new features are specific to Windows Server with Desktop Experience only. Some of these will require running the OS on physical systems AND having the right drivers on hand.

• Additions to <Settings>Accounts: Email & Accounts is now consistent with Windows 11. Please note, domain join will still be necessary for most scenarios.
  • Call to action: Please try adding Microsoft accounts and/or work accounts along with relevant apps that take advantage of this.
• Increased coverage for Bluetooth devices. Many of you want to use BT to connect mice, keyboards, and audio devices at the Edge. Please try out your favorite keyboard, mouse, headphones, or other BT peripheral!
  • Wi-Fi present by default. Many of you want to connect servers to Wi-Fi networks at the Edge. While Wireless LAN service has been present in Windows Server, it was disabled by default. Wi-Fi support is now currently enabled by default for Edge scenarios. You will need the appropriate hardware and drivers handy. Please verify that your wireless devices work properly. When hardware and the correct drivers are present, see the corresponding Settings and Taskbar experiences. Let us know what you think!

[NEW] SMB over QUIC alternative server port

Starting with Insider Build 26040, the SMB server now supports listening on an alternative network port for SMB over QUIC instead of hardcoded default. Previously, SMB over QUIC only supported QUIC(UDP)/443, but now you can choose any unused port from 1-65535. Windows Server Insider does not support configuring alternative SMB server TCP or RDMA ports at this time; if you organization has scenarios where it would be useful to configure those ports, message Ned Pyle, SMB PM, at About Ned Pyle - Microsoft Community Hub.

You can specify an alternative SMB over QUIC server port using the New-SmbServerAlternativePort PowerShell cmdlet.

For more information on using this option, review https://aka.ms/SMBAlternativePorts.

Known Issues​

Setup: Some users may experience overlapping rectangle voids following mouse clicks during "OOBE" setup. This is a graphics rendering issue and will not prevent setup from completing. 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.

The new Feedback Hub app is not functioning properly in this release due to known issues. These will be addressed in a future release. Please continue to submit feedback as described in the "We value your feedback!" section below.

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, 2024.

How to Download​

Registered Insiders may navigate directly to the Windows Server Insider Preview download page. If you have not yet registered as an Insider, see GETTING STARTED WITH SERVER on the Windows Insiders for Business portal.

We value your feedback!​

The most important part of the release cycle is to hear what's working and what needs to be improved, so your feedback is extremely valued. For Windows Server, use your registered Windows 10 or Windows 11 Insider device and use the Feedback Hub application. In the app, choose the Windows Server category and then the appropriate subcategory for your feedback. In the title of the Feedback, please indicate the build number you are providing feedback on as shown below to ensure that your issue is attributed to the right version:

[Server #####] Title of my feedback

See Give Feedback on Windows Server via Feedback Hub for specifics. The Windows Server Insiders space on the Microsoft Tech Communities supports preview builds of the next version of Windows Server. Use the forum to collaborate, share and learn from experts. For versions that have been released to general availability in market, try the Windows Server for IT Pro forum or contact Support for Business.

Diagnostic and Usage Information​

Microsoft collects this information over the internet to help keep Windows secure and up to date, troubleshoot problems, and make product improvements. Microsoft server operating systems can be configured to turn diagnostic data off, send Required diagnostic data, or send Optional diagnostic data. During previews, Microsoft asks that you change the default setting to Optional to provide the best automatic feedback and help us improve the final product.

Administrators can change the level of information collection through Settings. For details, see Configure Windows diagnostic data in your organization (Windows 10 and Windows 11) - Windows Privacy. Also see the Microsoft Privacy Statement.

Terms of Use​

This is pre-release software - it is provided for use "as-is" and is not supported in production environments. Users are responsible for installing any updates that may be made available from Windows Update. All pre-release software made available to you via the Windows Server Insider program is governed by the Insider Terms of Use.





ISO from Microsoft: