Announcing Windows Server Insider Preview Build 16257 Insider

    Announcing Windows Server Insider Preview Build 16257

    Announcing Windows Server Insider Preview Build 16257

    Category: Insider
    Posted: 08 Aug 2017

    Hello Windows Insiders!

    Today we are very excited to be releasing Windows Server Insider Preview Build 16257 to Windows Insiders. To access, register at the Windows Insiders for Business program or the Windows Insider program and then navigate to the Windows Server Insider Preview download page.

    This release also includes the Remote Server Administration Tools (RSAT) packages. When installed on a Windows 10 client, RSAT allows a user to remotely manage and administer Insider builds of Windows Server via GUI tools. Valid on Windows 10 client builds greater than 16250.

    General Scenario Highlights

    Developers and Containers:

    • New base container images (available on Windows Insider Docker Hub repo)
      • Optimized Nano Server base image (over 70% smaller)
        • The .NET team is providing a preview image based on Nano Server with .NET Core 2.0
        • The PowerShell team is providing a preview image based on PowerShell 6.0
      • Optimized Server Core base image (over 20% smaller)
    • Support for SMB volume mounting
    • Infrastructure for Orchestrators
      • Networking enhancements for ongoing Kubernetes work
      • Named pipe mapping support
    • Bug fixes, performance enhancements

    Cloud Guest:

    • IIS
      • TLS info: administrators can make specific recommendations to default to HTTPS
    • Disaster Recovery
      • Storage Replica Test Failover
    • Guest + Host better together
      • vPMEM in Guest: Tenants can use and manage PMEM/SCM
      • Tenant-Aware VM Start Ordering: App Ready / OS Heartbeat for better load balancing
      • Guest RDMA
    • Improvement in time accuracy
    • Azure enlightened clusters – optimized to run on Azure IaaS

    Cloud Host:

    • Software Defined Data Center (SDDC) host
      • Security
        • Shielded Linux VM
        • SDN: Encrypted virtual networks
        • Secure clusters
        • SMB 1 disabled by default
      • Resiliency and Availability
        • SDN: Reduced downtime for tenant connections through gateways
        • Spaces Direct: Scoped Spaces to mitigate impact of multi-node loss
        • Spaces Direct: Marginal drive handling for predictive detection of drive failures
      • Efficiency
        • Data Deduplication available for ReFS
        • New Data Deduplication DataPort API for optimized ingress/egress
        • Space efficiency with ReFS Compaction
        • Performant Spaces Direct Multi Resilient Volumes (MRV)
      • Hyper-converged Scale
        • Cluster Sets: Significantly increases hyper-converged SDDC cloud scale by grouping multiple clusters into a larger fabric
      • Hardware support
        • Support for Storage Class Memory (SCM) in Spaces Direct

    What’s New in Build 16257 for Windows Server

    Windows Subsystem for Linux (WSL) is available on Windows Server

    • Windows Subsystem for Linux (WSL) is now available on Windows Server along with a compliment of Linux distributions.
    • Test WSL on Windows Server. WSL runs unmodified Linux (ELF64) binaries natively. With the additions of WSL you can run node.js, Ruby, Python, Perl, Bash scripts or other tools that expect Linux behaviors, environment, or filesystem-layout, the ability to install and run Linux with WSL expands the tools at your disposal on Windows Server.
    • At this time, WSL does not support persistent Linux services (such as daemons and jobs) as background tasks. To enable WSL and install a Linux distribution, see Enable the Windows Subsystem for Linux and Install a Linux distribution in the Windows Server 2016 Installation Guide on GitHub.
    • Read more in this blog or follow the installation guide to try it out.

    Delivery Optimization is available for Windows Server

    Delivery Optimization has been the main downloader of Windows Update and Windows Store content since the Windows 10 Anniversary Update, providing faster and more reliable downloads. Starting in the latest builds for Server, Delivery Optimization is now the downloader used by Windows Update on Windows Server.Delivery Optimization can also provide Peer-to-peer bandwidth optimization between Windows Server machines. To enable peer-to-peer downloads open Settings -> Update & Security -> Advanced Options -> Delivery Optimization and turn ON the toggle to “Allow downloads from other PCs”.

    For more information on Delivery Optimization including configurations you can set via group policies or MDM policies please visit

    How to Download

    The latest Windows Server build and matching symbols are available for download here. Matching Windows Server container images will be available via the Docker Hub. For more information about Windows Server containers and Insider builds, please visit

    The following keys are available for unlimited activations of Windows Server. These keys may be used throughout the pre-release cycle.

    • Server Datacenter Core: B69WH-PRNHK-BXVK3-P9XF7-XD84W
    • Server Standard Core: V6N4W-86M3X-J77X3-JF6XW-D9PRV

    NOTE: If you signed up for Windows Insiders for Business using an AAD account, there is a temporary issue with access to the Windows Server Download page using AAD accounts. If you registered using an MSA account at the Windows Insider program, your MSA account may be used to access the page and to download builds until this is resolved.

    It’s all about your feedback!

    Use the Feedback Hub app to provide feedback on Windows Server builds. Feedback Hub comes pre-installed on Windows 10. Register a Windows 10 device with the Windows Insider or Windows Insider for Business programs. Open the Feedback Hub application. Choose the Server category and then the appropriate subcategory for your feedback. Please indicate what edition and build number you are providing feedback on. The Feedback Hub app cannot scan a server for diagnostic information, however you may manually attach screenshots or other files to your feedback entry.

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

    The expiration date for this server preview build is 12/4/2017.

    Known issues

    • The background tasks infrastructure service (Bisrv.dll) may cause a system crash because of a null class pointer read error (0xC0000005) or a failfast corrupt list entry (0xC0000409) during a Distributed Component Object Model (DCOM) launch, or because of a critical process bug check (error code 0xC0000409, bug check 0xEF) in the host process for Windows services (Svchost.exe).
    • Calling into the firewall service may hang: Apps that call into the firewall, such apps that use networking, may become unresponsive until the user reboots because of an application hang end-task error (0xCFFFFFFF) in the Windows firewall API library (FirewallAPI.dll), which occurs when the library is blocked on an advanced local procedure call (ALPC) port while attempting to diagnose a connection failure and retrieve information.
    • Cluster Sets: A couple of key functionalities to enable end-to-end testing of Cluster Sets scenarios are not present in this build, so defer all evaluation of this scenario to a future build.
    • Bugcheck during volume creation: A stop error may occur during volume creation in a cluster. The recommended workaround is, after restarting the computer, to delete the volume and try creation again.
    • Bugcheck during volume repair: A stop error may occur during volume repair in a cluster. The recommended workaround is to restart the computer. No corruption or data loss is expected.

    No downtime for Hustle-As-A-Service,

    Dona <3

    Brink's Avatar Posted By: Brink
    08 Aug 2017

  1. Posts : 4,666
    Windows 10 Pro x64 21H1 Build 19043.1151 (Branch: Release Preview)

    Anybody here testing Windows Server 2016 IPs?

    While waiting for next Win 10 build I will explore Srv 2016 Build 16257 :)
      My Computers

  2. Posts : 520
    Windows 10

    Played around with these a bit, because it's core you need to know the command line/powershell pretty good to get it up and running and able to connect to it.
      My Computer

  3. Posts : 4,666
    Windows 10 Pro x64 21H1 Build 19043.1151 (Branch: Release Preview)

    Yeah, but if on latest Win10 IP you should be able to manage the server remotely using the Remote Server Admin Tools. Whatever that involves...I have not yet tested this but working on it... :)
      My Computers

  4. Posts : 4,666
    Windows 10 Pro x64 21H1 Build 19043.1151 (Branch: Release Preview)

    I can't get RSAT to authenticate on this server. Not sure what I am doing wrong. I have gone through hundreds of documents, and nothing helps. The error message isn't that descriptive can be expected from Windows.

    On 2012R2 everything RSAT related works really good even for tens of servers, no problem. Giving up on 2016 IPs...
      My Computers


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