Announcing Windows Server vNext Preview Build 18945


Hello Windows Insiders!


Today we are pleased to release a new Insider preview build of the Windows Server VNext Semi-Annual Channel editions.


What's New 


Extending support for FIDO2 security keys to hybrid environments 

We’re adding the capability for modern passwordless credentials, such as FIDO2 security keys, to authenticate and provide seamless Single Sign-On (SSO) to on-premises environments.  Please refer to this blog entry that discusses this capability for cloud environments. Addition of this new capability will extend this feature to hybrid environments. 


Available Content


  • Windows Server vNext Semi-Annual Preview The Server Core Edition is available in the 18 supported Server languages in ISO format and in VHDX format in English only.
  • Windows Server Core App Compatibility FoD Preview
  • Windows Server Language Packs
  • Windows Admin Center 1907


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


The following keys allow for unlimited activations of Windows Server Semi-Annual Channel Previews

     Server Standard: V6N4W-86M3X-J77X3-JF6XW-D9PRV

     Server Datacenter: B69WH-PRNHK-BXVK3-P9XF7-XD84W

This Windows Server Preview will expire July 31st, 2020.

How to Download 


Registered Insiders may navigate directly to the Windows Server Insider Preview download page.  See the Additional Downloads dropdown for Windows Admin Center and other supplemental apps and products. 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 a frequent 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 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 as shown below:


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


See Share Feedback on Windows Server via Feedback Hub for specifics. We also encourage you to visit the Windows Server Insiders space on the Microsoft Tech Communities forum to collaborate, share and learn from experts.


For Windows Admin Center, Send us feedback via UserVoice. We also encourage you to visit the Windows Admin Center space on the Microsoft Tech Communities


Known Issues

There is an issue where the App Compatibility FOD cannot be added to the OS .wim image offline using DISM /image method.  After upgrade, it is necessary to reinstall the new FOD using DISM /online method.


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.


4 Replies

@Mary Hoffman Yeah adding App Compatibility FOD doesn't work once the build is installed either, gives an error code of 0x800f0950

We took a clean install of the 18945 build, applied the FoD, and were unable to reproduce the error code you are seeing. Were these the steps you followed? is there any other information you can provide about the steps that you took that resulted in this error?
I got it to work, I had to either mount the AppCompatibility ISO or copy the contents to a local drive. When I pointed it to a network share with the extracted contents of the ISO it did not work.
@ViolentCrow Thanks for reporting this. A fix will be coming in a future preview.