Windows Server Insiders topics

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!

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 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-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] 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

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.

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

Announcing Windows Server vNext Preview Build 29550

StaceyCL_RM — Mon, 23 Mar 2026 21:16:21 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 a release 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 resumes with preview build 29550 or later.

What's New

[NEW] ReFS Boot is enabled for Windows Server vNext preview builds.

- 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

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.

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 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

Windows Server Datacenter: Azure Edition preview build 29531 now available in Azure

StaceyCL_RM — Tue, 03 Mar 2026 17:25:17 GMT

Hello Windows Server Insiders!

We welcome you to try Windows Server vNext Datacenter: Azure Edition preview build 29531 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 29531 | Microsoft Community Hub.

The file Microsoft_Server_InsiderPreview_LangPack_FOD_29531.iso is missing language packs.

iLikeYi — Fri, 20 Feb 2026 08:24:10 GMT

Is it difficult to put these language packs in Microsoft_Server_InsiderPreview_LangPack_FOD_29531.iso?

WinRe.wim

PackageName	PackageState	ReleaseType	InstallTime
WinPE-DismCmdlets-Package~31bf3856ad364e35~amd64~~10.0.29531.1000	Installed	FeaturePack	2/7/2026 15:07
WinPE-DismCmdlets-Package~31bf3856ad364e35~amd64~en-US~10.0.29531.1000	Installed	LanguagePack	2/7/2026 15:07
WinPE-PlatformId-Package~31bf3856ad364e35~amd64~~10.0.29531.1000	Installed	FeaturePack	2/7/2026 15:06
WinPE-PlatformId-Package~31bf3856ad364e35~amd64~en-US~10.0.29531.1000	Installed	LanguagePack	2/7/2026 15:06
WinPE-PowerShell-Package~31bf3856ad364e35~amd64~~10.0.29531.1000	Installed	FeaturePack	2/7/2026 15:07
WinPE-PowerShell-Package~31bf3856ad364e35~amd64~en-US~10.0.29531.1000	Installed	LanguagePack	2/7/2026 15:07
WinPE-SecureBootCmdlets-Package~31bf3856ad364e35~amd64~~10.0.29531.1000	Installed	FeaturePack	2/7/2026 15:07
WinPE-SecureBootCmdlets-Package~31bf3856ad364e35~amd64~en-US~10.0.29531.1000	Installed	LanguagePack	2/7/2026 15:07
WinPE-UpdateOrchestrator-Package~31bf3856ad364e35~amd64~~10.0.29531.1000	Installed	FeaturePack	2/7/2026 15:08
WinPE-UpdateOrchestrator-Package~31bf3856ad364e35~amd64~en-US~10.0.29531.1000	Installed	LanguagePack	2/7/2026 15:09

Account blocked downloading any Insider ISO

OLDMAN2018 — Tue, 17 Feb 2026 02:54:33 GMT

Same basic message as the Google Fiber user, however, I know what caused my account to be blocked. I did not approve a Firewall request for Webview2 while using Server 2022 and Duck Browser (you know which one as I am not approving of nor recommending a non-MSFT issued browser here) to Download the ISO for Vnext on the Server Insider's Download page. I am still able to log into the page, select a build, choose my language, and I get the error after clicking Confirm. It also happened in Edge and on my cell phone using Cellular and it's proprietary browser. I installed 26534, and though it did allow me to attach my insider id to it, it would not dl a newer build, nor any Insider build for Windows 11 either. The page simply says to contact Microsoft support if you feel you got this in error. Of course, that would not accomplish anything except confuse some MSFT contacted Tech support and possibly incur a fee for me. You have my account info.
Any help clearing it would be appreciated.

Announcing Windows Server vNext Preview Build 29531

StaceyCL_RM — Mon, 23 Mar 2026 21:14:51 GMT

Hello Windows Server Insiders!

Build 29531 establishes 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 are not supported. We encourage all Windows Server vNext preview users to perform a clean install to reliably continue in the Windows Server vNext preview program.

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 a release 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 will resume with future vNext preview releases.

What's New

[NEW] 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

[NEW] ReFS Boot is enabled for Windows Server vNext preview builds.

- 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

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

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.

Download Windows Server Insider Preview (microsoft.com)

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

Developer Platform

New Build

New Windows Server vNext preview coming next week!

StaceyCL_RM — Thu, 05 Feb 2026 19:41:03 GMT

Hello Windows Server Insiders!

A new Windows Server vNext preview release is coming next week!

We have a number of features to share with you and can't wait to hear your feedback. Stay tuned!

Please note: Upgrades from earlier Windows Server preview builds are not supported. We encourage all Windows Server preview users to perform a clean install using this new baseline build once available.

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 a release of a new baseline build for our Server Insider Program.

The new baseline build will not be Flighted due to upgrade issues. Flighting support will resume with future preview releases.

How to Download

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

Developer Platform

New Build

Windows Server 2025 arm64

Fulco — Wed, 04 Feb 2026 17:45:31 GMT

Will there be an official release of Windows Server 2025 arm64? If so when?

The last Canary Cannel release worked fine on a M1 (or higher) Apple computer with the use of Parallels.

Shadow Copy with 6 days delay

ServetKaplan — Wed, 04 Feb 2026 14:07:48 GMT

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Shadow Copy
Windows Server 2022 Datacenter (VMWare 7.1)
The MaxShadowCopies registry value has been increased to 256.
Shadow Copies have been redirected to a different hard disk; FS=NTFS.
The schedule is set to run three times per day.
The maximum size is set to “Limit” with 1,700,000 MB.

Current issue:
Shadow Copies were available normally for several months.
Now, suddenly, the Shadow Copies are displayed with a 6‑day delay.

NTFS permissions are partially not working.

ServetKaplan — Wed, 04 Feb 2026 13:29:55 GMT

Participant A is sometimes unable to see Participant B’s files.
The issue can be resolved by clicking the option:
"Replace all child object permission entries with inheritable permission entries from this object."
However, the problem keeps reappearing.

Windows Server 2022 Datacenter (VMware 7.1), formatted as NTFS.

Windows Server Insiders Community

Jangk — Tue, 30 Dec 2025 01:16:27 GMT

Good job

Windows Server Datacenter: Azure Edition preview build 26534 now available in Azure

StaceyCL_RM — Tue, 09 Dec 2025 08:08:24 GMT

Hello Windows Server Insiders!

We welcome you to try Windows Server vNext Datacenter: Azure Edition preview build 26534 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 26534 | Microsoft Community Hub.

This is our last preview for 2025. Please join us in January 2026 for new features and new content!