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July 31, 2018

Announcing Windows Server 2019 Insider Preview Build 17723

Hello Windows Insiders!

Today we are pleased to release a new build of the Windows Server vNext Long-Term Servicing Channel (LTSC) release that contains both the Desktop Experience and Server Core in all 18 server languages, as well as a new build of the next Windows Server Semi-Annual Channel release in English. In addition, the first preview of Microsoft Hyper-V Server is included with this build.

In each preview release, there are two major areas that we would like you to try out:

In-place OS Upgrade (from Windows Server 2012 R2, Windows Server 2016 or a previous preview build). Build-to-Build upgrade is also supported.

Application compatibility – please let us know if any server roles or applications stops working or fails to function as it used to.

What’s New

Click here to see the full list of new functionality introduced in earlier builds of Windows Server.

System Insights

In this Insider build, you can add new predictive capabilities to System Insights, without requiring any OS updates. This functionality enables developers, including Microsoft and third parties, to create and deliver new capabilities mid-release to address the scenarios you care about. New developer documentation and resources are now available, which help you write your own custom capabilities.

Any new capability can integrate with and extend the existing System Insights infrastructure:

  • New capabilities can specify any performance counter or ETW event, which will be collected, persisted locally, and returned to the capability for analysis when the capability is invoked.
  • New capabilities can leverage the existing Windows Admin Center and PowerShell management planes. Not only will new capabilities be discoverable in System Insights, they also benefit from custom schedules and remediation actions.

Deploying Kubernetes on Windows Server

Kubernetes is a popular orchestration tool for containers (see What are Containers) that makes deployment and management intuitive, scalable, and effective. This includes built-in features such as:

  • Scheduling: Given a container image and a resource request, find a suitable machine on which to run the container.
  • Health monitoring: Watch for container failures and automatically reschedule them.
  • Networking: Provide a network for coordinating containers to communicate across machines.
  • Service Discovery: Enable containers to locate each other automatically even as they switch hosts or change IP addresses.
  • Scaling: Add or remove container instances to match demand, either manually or automatically.

And much more! For guidance that walks you through how to install Kubernetes onto your on-premise Windows datacenter, please see How To Guide: Kubernetes for Windows Flannel (Host-Gateway). For more information about container orchestrators in general, see Container orchestrators on

Congestion Control with LEDBAT

Keeping a network secure is a never-ending job for IT Pros, and doing so requires regularly updating systems to protect against the latest threat vectors.  This is one of the most common tasks that an IT Pro must perform.  Unfortunately, it can result in dissatisfaction for end-users as the network bandwidth used for the update can compete with interactive tasks that the end user requires to be productive.

With Windows Server 2019, we bring a latency optimized, network congestion control provider called LEDBAT which scavenges whatever network bandwidth is available on the network, and uses it

For a full write up detailing this improvement, please see our announcement LEDBAT – Latency Optimized Background Transport

What’s New in Additional Downloads

A new build of Server Core App Compatibility FoD Preview is available.

Available Content

  • Windows Server 2019 Preview is available in ISO format in 18 languages, and in VHDX format in English only. This build and all future pre-release builds will require use of activation keys during setup. The following keys allow for unlimited activations:
Datacenter Edition 6XBNX-4JQGW-QX6QG-74P76-72V67
Standard Edition MFY9F-XBN2F-TYFMP-CCV49-RMYVH
  • Windows Server vNext Semi-Annual Preview – The Server Core Edition is available in English only, in ISO or VHDX format. The images are pre-keyed – no need to enter a key during setup.
  • Microsoft Hyper-V Server
  • Windows Admin Center Preview 1807

Symbols are available on the public symbol server – see Update on Microsoft’s Symbol Server blog post and Using the Microsoft Symbol Server. Matching Windows Server container images will be available via Docker Hub. For more information about Windows Server containers and Insider builds, click here.

This build will expire December 14th, 2018.

How to Download 

To obtain the Insider software downloads, registered Insiders may navigate 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!

Use your registered Windows 10 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 in this format:

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

We also encourage you to visit the Windows Server Insiders space on the Microsoft Tech Communities forum to collaborate, share and learn from experts.

Known Issues

  • [NEW] On Nano Server, copying a file from an SMB volume in a container to local storage fails.
  • [NEW] A specific distributed search and analytics engine may by denied access when querying C:\Windows\temp\ as ContainerUser. To work around this issue, set the paths for temporary folders to another location. For example, by using setx:    setx /M TEMP “c:\sample”   setx /M TEMP “c:\sample”
  • [NEW] A Multi-Resilient Volume (MRV) may fail to mount during node maintenance for a software-defined datacenter (SDDC) cluster, causing virtual machines to go offline.
  • [NEW] Services.exe should not launch Upfc.exe when a system starts if the system is running inside of a container.
  • [NEW] On recent preview builds, database applications might not be able to initialize a database and fail with a stack overflow or insufficient privileges when the database is located on an SMB volume.
  • [NEW] Virtual machines stop unexpectedly with exit reason 3, and they migrate repeatedly every few minutes.
  • [NEW] Preview releases of the operating system, starting with build 17698, may fail to detect a specific family of RAID controllers.
  • [NEW] Shielded VMs running Linux do not boot. The loader (LSVMLoad) waits for a passphrase for the boot partition.
  • [NEW] Draining a node may fail with an error: “Cannot create a file when that file already exists. (0x800700b7).”
  • Creating or modifying environment variables by using setx fails on a system running in a Nano Container (that is, Nano Server as a container image). On an affected system, setx requires a specific path in the registry, HKCU\Environment\, to exist by default. You can work around this issue by changing where the variable is stored in the registry, or you can add the expected registry path before executing setx commands. To specify that the variable be set for system-wide use in HKLM rather than in HKCU, the default, add the /M switch to a setx command. To instead add the expected registry path, run reg add HKCU\Environment before executing setx commands.
  • The Virtual Machine Management Service (VMMS) may experience an error, APPLICATION_FAULT_INVALID_POINTER_READ, in Cluster Manager.

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 made available from Windows Update.   All pre-release software made available to you via the Windows Server Insider program are governed by the Insider Terms of Use.