Windows Server Insiders topics

Announcing Windows Server vNext Preview Build 29602

StaceyCL_RM — Mon, 08 Jun 2026 20:28:46 GMT

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 and Azure Edition (for VM evaluation only). Branding remains Windows Server 2025 in this preview - when reporting issues please refer to Windows Server vNext preview.

Build 29531 established a new Server preview baseline build. Please perform a clean install of Build 29531 (or later) using the installation media linked below.

Please note: Upgrades from Windows Server vNext preview builds older than 29531 are not supported. We encourage all Windows Server vNext preview users to perform a clean install using 29531 or later to successfully upgrade to future Windows Server vNext preview builds.

While upgrades from earlier Windows Server previews (Build 26525 and older) are not technically blocked by setup.exe, a number of known issues have been identified related to upgrades necessitating the establishment of a new baseline build for our Server vNext Preview Program.
The new baseline build (29531) will not be Flighted due to upgrade issues. Flighting support resumed with preview build 29550 or later.

What's New

Quick Machine Recovery available in Windows Server vNext Insider Previews.

Quick machine recovery (QMR) is now available for Server vNext Insiders to test. This feature enables the recovery of Windows Server devices when they encounter boot critical errors that prevent them from booting. QMR can automatically search for cloud‑based remediations to recover from widespread boot failures significantly reducing the burden on IT administrators when multiple devices are impacted. This supports the goals of the Windows Resiliency Initiative by enabling applicable fixes to be delivered through trusted Windows Update to restore affected devices, helping reduce downtime and minimize manual recovery efforts across enterprise environments.

This feature is currently enabled in the latest Server vNext Insider builds for customers to experience test mode. A Group Policy option to enable or disable the feature will be introduced in upcoming builds to provide additional administrative control.

To simulate the quick machine recovery experience, use the following commands from an elevated command prompt:

1. Enable test mode:

reagentc.exe /SetRecoveryTestmode

2. Configure Windows to boot to Windows Recovery Environment on the next boot:

reagentc.exe /BootToRe

3. Reboot your device.The system goes through autoremediation of a simulated crash safely and reboots back to Windows Server.

For more information, please review Quick machine recovery (QMR) and Windows Resiliency Initiative. When providing feedback using Feedback hub, please select QMR from the Recovery and Uninstall category in the app.

NVMe-over-Fabrics (NVMe-oF) extends the NVMe protocol—originally designed for local PCIe-attached SSDs—across a network fabric. Instead of using legacy SCSI-based protocols such as iSCSI or Fibre Channel, NVMe-oF allows a host to communicate directly with remote NVMe controllers using the same NVMe command set used for local devices. In this Insider build, Windows Server supports:

NVMe-oF over TCP (NVMe/TCP), allowing NVMe-oF to run over standard Ethernet networks without specialized hardware.
NVMe-oF over RDMA (NVMe/RDMA), enabling low-latency, high-throughput NVMe access over RDMA-capable networks (for example, RoCE or iWARP) using supported RDMA NICs.

For more information, please visit: Introducing the Windows NVMe-oF Initiator Preview in Windows Server Insiders Builds | Microsoft Community Hub

ReFS Boot is enabled for Windows Server vNext preview builds.

Known Limitations

ReFS Boot systems create a minimum 2GB WinRE partition.
When WinRE cannot be updated due to space constraints, the system may disable WinRE. Disabling WinRE does not remove the partition.
If the WinRE partition is deleted and the boot volume is extended over it, this operation is unrecoverable without a clean install.

For more information, please visit: Resilient File System (ReFS) overview | Microsoft Learn

Feedback Hub app is 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] A race condition in the TLS hybrid key exchange implementation may cause the LSASS service to crash when hybrid groups are negotiated by a TLS server. To avoid this issue until the fix is released, please disable hybrid groups (X25519_MLKEM768, SecP256r1_MLKEM768, SecP384r1_MLKEM1024) using TLS cmdlets or Group Policy, as outlined here.

Server Core Upgrades and AppCompat FOD: Enabling AppCompat FOD after reinstall may fail due to legacy 3rd-party license compatibility issues on Server Core devices. Server Core users may be unable to install the latest AppCompat FOD after upgrading to build 29574. This appears to be limited to Server Core installations with 3rd-party application licenses that fail compatibility checks after upgrade. This will be addressed in a future build.

Upgrading from older builds of Windows Server vNext previews (26525 or older) are not supported. Please perform a clean install of build 29531 or later. Users may experience failures when attempting to upgrade from earlier previews (build 26525 and older). VMs may fail to upgrade or start after upgrade from older preview builds impacting live migration and failover cluster scenarios.

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

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, 2026.

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. Please use the new Feedback Hub app for Windows Server if you are running a Desktop version of Server. If you are using a Core edition, or if you are unable to use the Feedback Hub app, you can 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 http://aka.ms/winserverdata. 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.

in-place upgrade fails from b29574 to latest vnext b29595

Karl-WE — Sat, 06 Jun 2026 12:32:00 GMT

Hi all,

is anyone facing the same issue IPU fails on a fresh b29574 upgrading to latest using WU?

provided more information in feedback hub. Thanks for sharing your experience.

as a next attempt I will mount ISO and upgrade. mind b29574 was the base bare metal installation so no previous IPUs involved.
related feedback https://aka.ms/AA11g03n

Installed roles:
- Hyper-V

Specialities:

tried SysWOW64 removal but failed to do so https://aka.ms/AA11eyy5
OS Drive is ReFS, potientially related https://aka.ms/AA11eyy8

<?xml version="1.0" encoding="utf-16"?> <SetupDiag xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="https://docs.microsoft.com/en-us/windows/deployment/upgrade/setupdiag"> <Version>1.7.0.0</Version> <ProfileName>FindRollbackFailure</ProfileName> <ProfileGuid>3A43C9B5-05B3-4F7C-A955-88F991BB5A48</ProfileGuid> <FailureData>0xc1900101-0x20017 Error: SetupDiag reports rollback failure found.Last Phase = FinalizeLast Operation = Cleanup external drivers after installationError = 0xC1900101-0x20017</FailureData> <FailureData>LogEntry: </FailureData> <FailureData>Refer to "https://docs.microsoft.com/en-us/windows/desktop/Debug/system-error-codes" for error information.</FailureData> <FailureDetails>RollbackErrorCode = 0xC1900101, ExtendedCode = 0x20017, LastOperation = Cleanup external drivers after installation, LastPhase = Finalize</FailureDetails> <Setup360Result>0xc1900101</Setup360Result> <Setup360Extended>0x20017</Setup360Extended> <SetupPhaseInfo> <PhaseName>Finalize</PhaseName> <PhaseStartTime>06/06/2026 13:16:53</PhaseStartTime> <PhaseEndTime>06/06/2026 13:17:35</PhaseEndTime> <PhaseTimeDelta>0:00:00:42.0000000</PhaseTimeDelta> <CompletedSuccessfully>true</CompletedSuccessfully> </SetupPhaseInfo> <SetupOperationInfo> <OperationName>Cleanup external drivers after installation</OperationName> <OperationStartTime>06/06/2026 13:17:35</OperationStartTime> <OperationEndTime>06/06/2026 13:17:35</OperationEndTime> <OperationTimeDelta>0:00:00:00.0000000</OperationTimeDelta> <CompletedSuccessfully>true</CompletedSuccessfully> </SetupOperationInfo> </SetupDiag>

also noticing uncommon links in root as if I were using FAT32.

BLOG: Windows Insiders - State of vbscript deprecation June 2026

Karl-WE — Sat, 06 Jun 2026 13:47:33 GMT

While I greatly appreciate the decision of vbscript / cscript / wscript removal, with security and hardening in mind – I would also appreciate if Microsoft could be actively using the vNext release channel, preparing for feature removal.

In sharing this summary, I am sharing my point of view that related changes indicating an adoption of the deprecation are not unveiled at that point.
This stands a bit contrary to the announcement, Microsoft intends removing the optional feature of vbscript by default with the upcoming release - anticipated by fall 2027.

Given my lessons learned from Secure Boot CA2023 exchange initiative, Microsoft guidance, foremost PowerShell based scripts, tooling and dashboards have been released quite late, looking at the timeline, considering the impact and scale customers had to deal with, and consequences for their security posture if they are not ready and done, with first certificates to expire soon.
Taking this learning into account and and projecting it to vbscript deprecration I come to the following conclusion:

SMB customers, enterprises, Microsoft Products, see below, are required to be updated or replaced, in order of adopting this change.
I believe there is quite some communication and learning curve required for users, admins, enterprises and OEMs in adopting the implicated change and including changed workflows and automation processes.

Looking forward to the next Windows Insider and esp. Windows Server Insider vNext builds!
Both Windows Insiders and Windows Server Insiders, also including ISV and OEMs may assist in reviewing and validating the new workflows required - assuming vbscript deprecation is in effect, as planned.

Without further ado, I am sharing my observations in regard to VBScript deprecation. I will try to keep this blogpost updated as soon I am aware about public facing changes.

Third-Party

AMD

Chipset drivers so far is one of the major non MSFT related blockers.

Suggestions:
Microsoft should initiate talks with AMD and other ISV and OEMs fixing their dependencies, also offering other solutions, see below.
Currently AMD Chipset drivers silently using vbscript calls checking for OS and HW platform compatibility. The installer fails when vbscript optional feature is removed.

OEM, ISV and Enterprise

Potentially affected:

expected dependencies for imaging, deployment and management workflows. Related or unrelated to Microsoft products.
LOB apps
custom Office Integration
logon and logoff scripts
setup and installers

Recommendation:
Please observe vbscript related events in Windows Event Viewer at scale using PowerShell, Remoting or Windows Event Subscriptions:

VBScriptDeprecationAlert Event ID 4096 VBScript is scheduled for deprecation. Our telemetry indicates that your system is currently utilizing VBScript. We strongly recommend identifying and migrating away from any VBScript dependencies at the earliest. The following process has been detected as using VBScript. The associated process tree and call stack are provided below to assist in identifying the scenario in which VBScript was invoked.

Microsoft

Windows Server and Client OS

affected: slmgr.vbs / printer management vbscripts / product activation logic and UX,
setup.exe, slui.exe

Office 2024 LTSC
affected: slmgr.vbs / ospp.vbs / Office deployment toolkit / product activation logic
Microsoft has placed a new PowerShell based script into the respective OSPP folder.
This script however is rather offering on checking licensing and cannot activate the Office product at this time.

Microsoft 365 Business, Enterprise, Home, Family
Affected: ospp.vbs
despite being subscription based will also trouble with activation once vbscript is removed

Sconfig
Related to product activation. no changes so far, relies on external changes. The script itself is safe to comply with the change, now it has been reworked and updated using PowerShell , starting Windows Server 2022.

WinRM
Affected: the whole WinRM configuration command, e.g. winrm qc

Windows Server Roles and Features: KMS / ADBA

Potentially affected as they rely on slmgr for adding and removing CSVLK keys.

Windows Server Roles and Features: IIS
legacy IIS extension management.

Windows Server Roles and Features: WSUS
related deployment and configuration scripts.

Windows Server Roles and Features: KMS / ADBA

potentially affected as they rely on slmgr for adding.

System Center Products incl. ConfigMgr
there might be depencendies for OS deployments in regard to OS imaging.

ADK, esp. Windows Imaging Tools and VAMT 3
potentially affected. Need to adopt changes in regard to activation and other operations.

Suggestions:

Recommending all these scripts being converted using Claude or Copilot from vbscript to PowerShell.
Providing a serviceable PS modules, especially for printer management, product activation, which enables enterprises to automate their activations and printers, even though Microsoft is going to remove vbscript. The modules should be improved for existing day two adminstration tasks and workflows. slmgr, in particular, had some nuances that were tedious such as identifying and removing (stale) activation keys.
Existing tools like slmgr and other will not work well in remoting. They do something but their interactive parts and outputs are reserved for interactive user sessions. Example: you can use slmgr in a remote PowerShell session for installing and activating a key but therer is no result return to the shell.
Combining slui.exe and slmgr.vbs into aforementioned improvements in functionality and syntax.
Consider support for PowerShell 7 in WinRE and Offline Setup phase.

Many thanks for your consideration!

Directory: C:\Windows\System32\Printing_Admin_Scripts\en-US Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 10:43 AM 98756 prncnfg.vbs -a--- 4/16/2026 10:43 AM 66172 prndrvr.vbs -a--- 4/16/2026 10:43 AM 62698 prnjobs.vbs -a--- 4/16/2026 10:43 AM 95908 prnmngr.vbs -a--- 4/16/2026 10:43 AM 71616 prnport.vbs -a--- 4/16/2026 10:43 AM 44278 prnqctl.vbs -a--- 4/16/2026 10:43 AM 22612 pubprn.vbs Directory: C:\Windows\System32 Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 4119 CallUxxProvider.vbs -a--- 4/16/2026 9:14 AM 145712 slmgr.vbs -a--- 4/16/2026 9:14 AM 1720 SyncAppvPublishingServer.vbs -a--- 4/16/2026 9:14 AM 204072 winrm.vbs Directory: C:\Windows\SysWOW64\Printing_Admin_Scripts\en-US Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 10:43 AM 98756 prncnfg.vbs -a--- 4/16/2026 10:43 AM 66172 prndrvr.vbs -a--- 4/16/2026 10:43 AM 62698 prnjobs.vbs -a--- 4/16/2026 10:43 AM 95908 prnmngr.vbs -a--- 4/16/2026 10:43 AM 71616 prnport.vbs -a--- 4/16/2026 10:43 AM 44278 prnqctl.vbs -a--- 4/16/2026 10:43 AM 22612 pubprn.vbs Directory: C:\Windows\SysWOW64 Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 145712 slmgr.vbs -a--- 4/16/2026 9:14 AM 204072 winrm.vbs Directory: C:\Windows\WinSxS\amd64_microsoft-windows-a..nagement-appvclient_31bf3856ad364e35_10.0.29574.1000_none_0895f7c27f109b8a Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 1720 SyncAppvPublishingServer.vbs Directory: C:\Windows\WinSxS\amd64_microsoft-windows-iis-legacyscripts_31bf3856ad364e35_10.0.29574.1000_none_ba69ed912e209e30 Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 98133 adsutil.vbs -a--- 4/16/2026 9:14 AM 41401 IIsExt.vbs Directory: C:\Windows\WinSxS\amd64_microsoft-windows-p..inscripts.resources_31bf3856ad364e35_10.0.29574.1000_en-us_ 4ad0e09e0339f1ef Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 10:43 AM 98756 prncnfg.vbs -a--- 4/16/2026 10:43 AM 66172 prndrvr.vbs -a--- 4/16/2026 10:43 AM 62698 prnjobs.vbs -a--- 4/16/2026 10:43 AM 95908 prnmngr.vbs -a--- 4/16/2026 10:43 AM 71616 prnport.vbs -a--- 4/16/2026 10:43 AM 44278 prnqctl.vbs -a--- 4/16/2026 10:43 AM 22612 pubprn.vbs Directory: C:\Windows\WinSxS\amd64_microsoft-windows-s..r-core-mgmtprovider_31bf3856ad364e35_10.0.29574.1000_none_62cec50667f8da2a Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 4119 CallUxxProvider.vbs Directory: C:\Windows\WinSxS\amd64_microsoft-windows-security-spp-tools_31bf3856ad364e35_10.0.29574.1000_none_81bcc6c67609fdb9 Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 145712 slmgr.vbs Directory: C:\Windows\WinSxS\amd64_microsoft-windows-w..for-management-core_31bf3856ad364e35_10.0.29574.1000_none_0688f60763f16bc8 Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 204072 winrm.vbs Directory: C:\Windows\WinSxS\amd64_updateservices-services_31bf3856ad364e35_10.0.29574.1000_none_bae89f3176313538 Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 8332 DynamicCompression.vbs -a--- 4/16/2026 9:14 AM 4289 SetAppPool.vbs -a--- 4/16/2026 9:14 AM 5813 SetMimeMap.vbs Directory: C:\Windows\WinSxS\wow64_microsoft-windows-iis-legacyscripts_31bf3856ad364e35_10.0.29574.1000_none_c4be97e36281602b Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 41401 IIsExt.vbs Directory: C:\Windows\WinSxS\wow64_microsoft-windows-p..inscripts.resources_31bf3856ad364e35_10.0.29574.1000_en-us_ 55258af0379ab3ea Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 10:43 AM 98756 prncnfg.vbs -a--- 4/16/2026 10:43 AM 66172 prndrvr.vbs -a--- 4/16/2026 10:43 AM 62698 prnjobs.vbs -a--- 4/16/2026 10:43 AM 95908 prnmngr.vbs -a--- 4/16/2026 10:43 AM 71616 prnport.vbs -a--- 4/16/2026 10:43 AM 44278 prnqctl.vbs -a--- 4/16/2026 10:43 AM 22612 pubprn.vbs Directory: C:\Windows\WinSxS\wow64_microsoft-windows-security-spp-tools_31bf3856ad364e35_10.0.29574.1000_none_8c117118aa6abfb4 Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 145712 slmgr.vbs Directory: C:\Windows\WinSxS\wow64_microsoft-windows-w..for-management-core_31bf3856ad364e35_10.0.29574.1000_none_10dda05998522dc3 Mode LastWriteTime Length Name ---- ------------- ------ ---- -a--- 4/16/2026 9:14 AM 204072 winrm.vbs

related announcements:

https://techcommunity.microsoft.com/blog/Windows-ITPro-blog/vbscript-deprecation-timelines-and-next-steps/4148301

Windows Server vNext cannot be activated

Karl-WE — Fri, 05 Jun 2026 07:39:51 GMT

Error Code 0xC004F012 when trying to activate WS vNext Datacenter with Key 2KNJJ-33Y9H-2GXGX-KMQWH-G6H67.

vbscript is removed, implying the future removal of this component from the OS.

It appear that Windows Activation still relying on vbscript. Is this something that is on the roadmap?

Would wish for native PowerShell support / module instead of vbscript.

Windows Server Datacenter: Azure Edition preview build 29595 now available in Azure

StaceyCL_RM — Wed, 27 May 2026 19:16:12 GMT

Hello Windows Server Insiders!

We welcome you to try Windows Server vNext Datacenter: Azure Edition preview build 29595 in both Desktop experience and Core version on the Microsoft Server Operating Systems Preview offer in Azure. Azure Edition is optimized for operation in the Azure environment. For additional information, see Preview: Windows Server VNext Datacenter (Azure Edition) for Azure Automanage on Microsoft Docs. For more information about this build, see Announcing Windows Server vNext Preview Build 29595 | Microsoft Community Hub.

Announcing Windows Server vNext Preview Build 29595

StaceyCL_RM — Tue, 26 May 2026 17:02:07 GMT

Hello Windows Server Insiders!

Build 29531 established a new Server preview baseline build. Please perform a clean install of Build 29531 (or later) using the installation media linked below.

While upgrades from earlier Windows Server previews (Build 26525 and older) are not technically blocked by setup.exe, a number of known issues have been identified related to upgrades necessitating the establishment of a new baseline build for our Server vNext Preview Program.
The new baseline build (29531) will not be Flighted due to upgrade issues. Flighting support resumed with preview build 29550 or later.

What's New

Quick Machine Recovery available in Windows Server vNext Insider Previews.

To simulate the quick machine recovery experience, use the following commands from an elevated command prompt:

1. Enable test mode:

reagentc.exe /SetRecoveryTestmode

2. Configure Windows to boot to Windows Recovery Environment on the next boot:

reagentc.exe /BootToRe

3. Reboot your device. The system goes through autoremediation of a simulated crash safely and reboots back to Windows Server.

NVMe-oF over TCP (NVMe/TCP), allowing NVMe-oF to run over standard Ethernet networks without specialized hardware.
NVMe-oF over RDMA (NVMe/RDMA), enabling low-latency, high-throughput NVMe access over RDMA-capable networks (for example, RoCE or iWARP) using supported RDMA NICs.

For more information, please visit: Introducing the Windows NVMe-oF Initiator Preview in Windows Server Insiders Builds | Microsoft Community Hub

ReFS Boot is enabled for Windows Server vNext preview builds.

Known Limitations

ReFS Boot systems create a minimum 2GB WinRE partition.
When WinRE cannot be updated due to space constraints, the system may disable WinRE. Disabling WinRE does not remove the partition.
If the WinRE partition is deleted and the boot volume is extended over it, this operation is unrecoverable without a clean install.

For more information, please visit: Resilient File System (ReFS) overview | Microsoft Learn

Known Issues

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, 2026.

How to Download

We value your feedback!

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

See Give Feedback on Windows Server via Feedback Hub for specifics.

Diagnostic and Usage Information

Administrators can change the level of information collection through Settings. For details, see http://aka.ms/winserverdata. Also see the Microsoft Privacy Statement.

Terms of Use

Windows Server Datacenter: Azure Edition preview build 29585 now available in Azure

StaceyCL_RM — Fri, 15 May 2026 20:38:42 GMT

Hello Windows Server Insiders!

We welcome you to try Windows Server vNext Datacenter: Azure Edition preview build 29585 in both Desktop experience and Core version on the Microsoft Server Operating Systems Preview offer in Azure. Azure Edition is optimized for operation in the Azure environment. For additional information, see Preview: Windows Server VNext Datacenter (Azure Edition) for Azure Automanage on Microsoft Docs. For more information about this build, see Announcing Windows Server vNext Preview Build 29585 | Microsoft Community Hub.

Announcing Windows Server vNext Preview Build 29585

StaceyCL_RM — Mon, 11 May 2026 17:06:03 GMT

Hello Windows Server Insiders!

Build 29531 established a new Server preview baseline build. Please perform a clean install of Build 29531 (or later) using the installation media linked below.

While upgrades from earlier Windows Server previews (Build 26525 and older) are not technically blocked by setup.exe, a number of known issues have been identified related to upgrades necessitating the establishment of a new baseline build for our Server vNext Preview Program.
The new baseline build (29531) will not be Flighted due to upgrade issues. Flighting support resumed with preview build 29550 or later.

Please join us this week for Windows Server Summit 2026

Windows Server Summit 2026 is happening this week (May 11 - May 13). Please join us for this online event to learn about the latest updates in Windows Server 2025 and what's coming in vNext. For more information and to register, please visit Windows Server Summit - May 11-13, 2026 - Microsoft Event page.

What's New

Quick Machine Recovery available in Windows Server vNext Insider Previews.

This feature is currently enabled in the latest Server vNext Insider builds for customers to experience test mode. A Group Policy option to enable or disable the feature will be introduced in upcoming builds to provide additional administrative control.

To simulate the quick machine recovery experience, use the following commands from an elevated command prompt:

1. Enable test mode:

reagentc.exe /SetRecoveryTestmode

2. Configure Windows to boot to Windows Recovery Environment on the next boot:

reagentc.exe /BootToRe

3. Reboot your device. The system goes through autoremediation of a simulated crash safely and reboots back to Windows Server.

NVMe-oF over TCP (NVMe/TCP), allowing NVMe-oF to run over standard Ethernet networks without specialized hardware.
NVMe-oF over RDMA (NVMe/RDMA), enabling low-latency, high-throughput NVMe access over RDMA-capable networks (for example, RoCE or iWARP) using supported RDMA NICs.

For more information, please visit: Introducing the Windows NVMe-oF Initiator Preview in Windows Server Insiders Builds | Microsoft Community Hub

ReFS Boot is enabled for Windows Server vNext preview builds.

Known Limitations

ReFS Boot systems create a minimum 2GB WinRE partition.
When WinRE cannot be updated due to space constraints, the system may disable WinRE. Disabling WinRE does not remove the partition.
If the WinRE partition is deleted and the boot volume is extended over it, this operation is unrecoverable without a clean install.

For more information, please visit: Resilient File System (ReFS) overview | Microsoft Learn

Known Issues

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, 2026.

How to Download

We value your feedback!

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

See Give Feedback on Windows Server via Feedback Hub for specifics.

Diagnostic and Usage Information

Administrators can change the level of information collection through Settings. For details, see http://aka.ms/winserverdata. Also see the Microsoft Privacy Statement.

Terms of Use

CXL Memory Expansion on WinServer 2025

isheaffer — Fri, 01 May 2026 15:45:04 GMT

I'm looking to find out if on window server 2025 is CXL Type 3 in memory expansion mode is validated "GA" and if so which cxl devices. I'm having issues finding this information. Anyone know and able to share?

Windows Server Datacenter: Azure Edition preview build 29574 now available in Azure

StaceyCL_RM — Wed, 29 Apr 2026 17:16:00 GMT

Hello Windows Server Insiders!

We welcome you to try Windows Server vNext Datacenter: Azure Edition preview build 29574 in both Desktop experience and Core version on the Microsoft Server Operating Systems Preview offer in Azure. Azure Edition is optimized for operation in the Azure environment. For additional information, see Preview: Windows Server VNext Datacenter (Azure Edition) for Azure Automanage on Microsoft Docs. For more information about this build, see Announcing Windows Server vNext Preview Build 29574 | Microsoft Community Hub.

Announcing Windows Server vNext Preview Build 29574

StaceyCL_RM — Mon, 27 Apr 2026 17:07:00 GMT

Hello Windows Server Insiders!

Build 29531 established a new Server preview baseline build. Please perform a clean install of Build 29531 (or later) using the installation media linked below.

While upgrades from earlier Windows Server previews (Build 26525 and older) are not technically blocked by setup.exe, a number of known issues have been identified related to upgrades necessitating the establishment of a new baseline build for our Server vNext Preview Program.
The new baseline build (29531) will not be Flighted due to upgrade issues. Flighting support resumed with preview build 29550 or later.

What's New

[NEW] Introducing Quick Machine Recovery in Windows Server vNext Insider Previews.

To simulate the quick machine recovery experience, use the following commands from an elevated command prompt:

1. Enable test mode:

reagentc.exe /SetRecoveryTestmode

2. Configure Windows to boot to Windows Recovery Environment on the next boot:

reagentc.exe /BootToRe

3. Reboot your device. The system goes through autoremediation of a simulated crash safely and reboots back to Windows Server.

NVMe-oF over TCP (NVMe/TCP), allowing NVMe-oF to run over standard Ethernet networks without specialized hardware.
NVMe-oF over RDMA (NVMe/RDMA), enabling low-latency, high-throughput NVMe access over RDMA-capable networks (for example, RoCE or iWARP) using supported RDMA NICs.

For more information, please visit: Introducing the Windows NVMe-oF Initiator Preview in Windows Server Insiders Builds | Microsoft Community Hub

ReFS Boot is enabled for Windows Server vNext preview builds.

Known Limitations

ReFS Boot systems create a minimum 2GB WinRE partition.
When WinRE cannot be updated due to space constraints, the system may disable WinRE. Disabling WinRE does not remove the partition.
If the WinRE partition is deleted and the boot volume is extended over it, this operation is unrecoverable without a clean install.

For more information, please visit: Resilient File System (ReFS) overview | Microsoft Learn

Known Issues

Upgrading from earlier builds of Windows Server vNext previews (26525 or older) are not supported. Please perform a clean install of build 29531 or later. Users may experience failures when attempting to upgrade from earlier previews (build 26525 and older). VMs may fail to upgrade or start after upgrade from older preview builds impacting live migration and failover cluster scenarios.

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, 2026.

How to Download

We value your feedback!

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

See Give Feedback on Windows Server via Feedback Hub for specifics.

Diagnostic and Usage Information

Administrators can change the level of information collection through Settings. For details, see http://aka.ms/winserverdata. Also see the Microsoft Privacy Statement.

Terms of Use

Windows Server Datacenter: Azure Edition preview build 29558 now available in Azure

StaceyCL_RM — Wed, 01 Apr 2026 17:23:53 GMT

Hello Windows Server Insiders!

We welcome you to try Windows Server vNext Datacenter: Azure Edition preview build 29558 in both Desktop experience and Core version on the Microsoft Server Operating Systems Preview offer in Azure. Azure Edition is optimized for operation in the Azure environment. For additional information, see Preview: Windows Server VNext Datacenter (Azure Edition) for Azure Automanage on Microsoft Docs. For more information about this build, see Announcing Windows Server vNext Preview Build 29558 | Microsoft Community Hub.

Announcing Windows Server vNext Preview Build 29558

StaceyCL_RM — Thu, 26 Mar 2026 17:40:54 GMT

Hello Windows Server Insiders!

Build 29531 established a new Server preview baseline build. Please perform a clean install of Build 29531 (or later) using the installation media linked below.

Please note: Upgrades from earlier Windows Server vNext preview builds older than 29531 are not supported. We encourage all Windows Server vNext preview users to perform a clean install using 29531 or later to successfully upgrade to future Windows Server vNext preview builds.

While upgrades from earlier Windows Server previews (Build 26525 and older) are not technically blocked by setup.exe, a number of known issues have been identified related to upgrades necessitating the establishment of a new baseline build for our Server vNext Preview Program.
The new baseline build (29531) will not be Flighted due to upgrade issues. Flighting support resumed with preview build 29550 or later.

What's New

NVMe-oF over TCP (NVMe/TCP), allowing NVMe-oF to run over standard Ethernet networks without specialized hardware.
NVMe-oF over RDMA (NVMe/RDMA), enabling low-latency, high-throughput NVMe access over RDMA-capable networks (for example, RoCE or iWARP) using supported RDMA NICs.

For more information, please visit: Introducing the Windows NVMe-oF Initiator Preview in Windows Server Insiders Builds | Microsoft Community Hub

ReFS Boot is enabled for Windows Server vNext preview builds.

Known Limitations

- ReFS Boot systems create a minimum 2GB WinRE partition.
- When WinRE cannot be updated due to space constraints, the system may disable WinRE. Disabling WinRE does not remove the partition.
- If the WinRE partition is deleted and the boot volume is extended over it, this operation is unrecoverable without a clean install.

For more information, please visit: Resilient File System (ReFS) overview | Microsoft Learn

Known Issues

[NEW] Thin Provisioning fails on clean installs in this build (29558).

Users selecting Thin Provisioning when attempting clean installs of this build may experience failures. This issue is understood and will be fixed in a future release.

Upgrading from earlier builds of Windows Server vNext previews (26525 or older) are not supported. Please perform a clean install of build 29531 or later.

Users may experience failures when attempting to upgrade from earlier previews (build 26525 and older). VMs may fail to upgrade or start after upgrade from older preview builds impacting live migration and failover cluster scenarios.

Download Windows Server Insider Preview (microsoft.com)

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

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, 2026.

How to Download

We value your feedback!

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

See Give Feedback on Windows Server via Feedback Hub for specifics.

Diagnostic and Usage Information

Administrators can change the level of information collection through Settings. For details, see http://aka.ms/winserverdata. Also see the Microsoft Privacy Statement.

Terms of Use

Experiences Creating a CA with ML‑DSA Using Microsoft Smart Card Key Storage Provider (ADCS / PQC)

srose — Tue, 24 Mar 2026 12:01:46 GMT

Hi all,

I’m exploring the possibility of using post‑quantum cryptography within an Active Directory Certificate Services (ADCS) environment in the Insider release 29550. Specifically, I’m interested in creating a Certificate Authority (CA) where the CA’s key material is generated and stored using a Microsoft Smart Card Key Storage Provider (KSP) with support for ML‑DSA. This is an option selectable in the "Specify the cryptographic options".

Has anyone in the community successfully done the following:

Created a CA using ML‑DSA: Micosoft Smart Card KSP as the cryptographic provider?

If so, what smart card or hardware token did you use that supports ML‑DSA via the Microsoft Smart Card KSP?

(e.g., specific vendor and/or model that exposes ML‑DSA support correctly to Windows)

Is it actually possible to create a CA using ML‑DSA as the cryptographic provider?

If yes, what are the key steps or gotchas?

What changes when ML‑DSA is used as the CA key provider compared to traditional providers like RSA/ECC?

Any differences in certificate creation, enrollment, templates, compatibility with clients, etc.?

Is there any official documentation for using ML‑DSA or PQC with ADCS?

Are there other post‑quantum cryptographic (PQC) options already supported or coming soon in ADCS?

Build 29550 Bare Metal ReFS Boot: Server Roles installation fails with 0xc004000d and/or 0x800f0922

Key13bb — Mon, 23 Mar 2026 21:02:25 GMT

When installing Windows Server Build 29550 on Bare Metal with the OS drive (C:) formatted as ReFS, the installation of core Server Roles (DHCP, Hyper-V, DNS, Windows Server Backup) fails consistently.

Error returned by PowerShell (Install-WindowsFeature) and/or Server Manager: 0xc004000d (One or several parent features are disabled). CBS.log shows TiWorker failing with [HRESULT = 0x800f0922 - CBS_E_INSTALLERS_FAILED].

Troubleshooting done:

Same ISO on KVM (formatted as NTFS) works perfectly.
Same hardware, formatted as ReFS on older Build 29531, worked perfectly.
"Leaf" features like Media Foundation install fine, but complex roles fail.
sfc /scannow did not find any integrity violation
DISM RestoreHealth fails with 0x80004005

Conclusion: There is a CBS / Hard Link regression when reading the Component Store (WinSxS) on a ReFS boot drive in build 29550.

Capabilities of NVMe-oF so far?

dd000 — Wed, 18 Mar 2026 13:41:19 GMT

Started playing around with NVMe-oF last night and got a successful connection to TrueNAS.

I'm wondering what the current capabilities/limitations are.

As far as I can tell you can't cluster the disk which is what I was primarily interested in.

I was able to connect the same NQN endpoint to two servers but the WSFC cluster wouldn't detect it as a cluster available disk.

Also the disks seems to disappear on every reboot and has to be set up again, so is there no auto-mount yet?

I understand this is early preview so I don't have many expectations, just would like some clarity.

Thank you.

Windows Server Datacenter: Azure Edition preview build 29550 now available in Azure

StaceyCL_RM — Tue, 17 Mar 2026 17:13:55 GMT

Hello Windows Server Insiders!

We welcome you to try Windows Server vNext Datacenter: Azure Edition preview build 29550 in both Desktop experience and Core version on the Microsoft Server Operating Systems Preview offer in Azure. Azure Edition is optimized for operation in the Azure environment. For additional information, see Preview: Windows Server VNext Datacenter (Azure Edition) for Azure Automanage on Microsoft Docs. For more information about this build, see Announcing Windows Server vNext Preview Build 29550 | Microsoft Community Hub.

Windows NVMe-oF Initiator connect error

pkovar — Tue, 17 Mar 2026 10:16:12 GMT

Hi everyone,
I am trying to test the new Windows NVMe-oF Initiator within build 29550.1000 but I am not able to connect to a remote storage array - getting the error
"IOCTL_NVMEOF_CONNECT_CONTROLLER failed with error code 0x1f" (see screenshot).
Any idea what does this error mean or what can be wrong?

Windows NVMe-oF Initiator

pkovar — Mon, 16 Mar 2026 14:59:56 GMT

Hi everyone,
I am trying to test the new Windows NVMe-oF Initiator within build 29550.1000 but I am not able to configure an I/O Subsystem Port, still getting the message "

A Host Gateway with the specified identifier was not found for the Initiator Adapter." (see screenshot).
Any idea what I am doing wrong?

Citrix Terminal Server Explorer (network drive) suddenly closes

ServetKaplan — Mon, 16 Mar 2026 09:12:22 GMT

Windows Explorer sessions on the Citrix terminal server that access a file server (Network Drive) close unexpectedly during file operations.

Citrix Terminal Server (Windows 2022)
File Server (Windows 2022)

Have somebody an Idea?

Kind Regards