Windows 10X development tools release notes


We recently announced some changes in the prioritization for Windows 10 and Windows 10X. These announcements include changes to the Windows 10X form factor priorities. Read more here.


This article describes functionality and guidance that is in public preview and may be substantially modified before it's generally available. Microsoft makes no warranties, express or implied, with respect to the information provided here. The functionality and APIs described here are available in the emulator image and SDK version listed on the Get Windows dev tools page, but may not be available elsewhere.


Microsoft Emulator and Windows 10X Emulator: build 19578 update

Previous releases

Windows Developer Blog

The Windows Developer Blog is the official source of product insight Windows developers. You can find in-depth information about the Microsoft Emulator releases in the following posts:


Microsoft Emulator and Windows 10X Emulator build 19578 update

This release includes Microsoft Emulator version and Windows 10X Emulator Image Preview version 10.0.19578.0.

In addition to the specific issues listed here, this update includes many updates to the Windows 10X operating system as well as the Win32 Container.


  • The Microsoft Emulator Manager now includes the ability to query the Store for updated Images.
    • On first run of the emulator, if there are no images installed, it will prompt to download the latest image.
    • You can also check for new images through the File->Download emulator images menu item.

Windows 10X image

  • The Windows 10X Emulator Image (build 19578) includes a new EULA that no longer requires it to be installed on an Insider Preview version of Windows. You can install it on Windows 10 version 10.0.17763.0 or higher to test existing apps on the dual-screen device emulator.
    • In order to use an Insider Preview SDK, developers must setup their dev environment on a Insider Preview version of Windows.
  • This update applies the windowing model for Windows 10X to your Win32 apps running in the container. System-defined window placement ensures that users have a consistent and simplified windowing experience that is tailored and appropriate to a smaller, dual-screen, and touch-friendly device. Some gaps remain and will be addressed in a future update.
  • An early version of File Manager (labeled Beta) is included. It is designed to work with OneDrive synced files and therefore requires a Microsoft account attached to the OS, either through the Settings app or by signing into a Microsoft app such as the Store.
  • Installing the Visual Studio Remote Tools no longer prompts about the Machine.config files during install.
  • Emulator displays "The GPU is not running. Problem code: 43". There is a recent regression that fails to initialize the GPU if the host machine is an older build than the Windows 10X image.
  • The LockScreen may stop responding. If it does, use the device portal and restart the ModernShellUXApp.exe process.
  • Occasionally, apps running in the Win32 Container may not display correctly. Tapping the tile in the taskbar typically brings up the app properly.

Debugging scenarios

  • When using Universal authentication, the bug that blocked re-deployment of MSIX packaged .NET apps has been fixed.
  • When debugging non-packaged C++, the mapping of the DevelopmentFiles folder does not persist across reboot of the emulator.

Microsoft Emulator and Windows 10X Emulator M365 DevDays release

This release includes Emulator version and Windows 10X Emulator Preview version 10.0.19563.0.

Emulator app

  • If the emulator freezes during POST (at the Hyper-V splash screen), disable GPU virtualization. This is found in the emulator manager app. Click edit under the installed emulator image and check the box next to Disable GPU. The emulator should now boot normally.
  • The emulator is unable to boot images moved off the system drive.
  • The emulator doesn't always resume after a running image goes to sleep. If you leave the emulator running for awhile and see a black screen instead of Windows 10X, click the X in the emulator toolbar to shut down the emulator. Then you can boot the emulator normally.
  • The Windows 10X emulator image currently enables diagnostics network ports and features used for OS development & validation. These facilities are unsupported and will be removed or disabled in future updates.

Windows 10X image

  • To improve the developer flow, the emulator build does not provide a first-boot experience with language/region selection, account logon etc. Therefore, suggestions in the “Recent” section of the Start menu, the lock experience and others may not function as expected.
  • The applications preloaded to the image will continue to be updated, and applications may be removed and new applications will be added. For instance, only the Chromium based version of the Edge browser will be preloaded in future releases.

Visual Studio Remote Tools 2017 and 2019

  • In Windows 10X running in the emulator, Windows Defender Application Control needs to be disabled to install the remote tools. This setting is under Apps. Change the dropdown under Choose which apps to install from Verified and reputable apps to All apps (not recommended).
  • When installing you will see an error message, like the one pictured below, a few times. You can safely click Ignore when you see this message, and the installer will complete normally.

remote tools installer error

MSIX-packaged projects

  • When using Universal Authentication, redeployment of MSIX packaging projects will error due to a system lock on one or more deployed files.
    • For C++ projects, reboot the emulator before redeploying your project (the Visual Studio Remote Tools is currently unsupported).
    • For .NET projects, use the Visual Studio Remote Tools instead, and configure the packaging project in your solution for remote debugging with no authentication.
      • Follow the configuration instructions for MSIX packaged apps, but set Authentication mode to None.
  • After your project deploys and activates, you might not see your app's window appear in the emulator. Check the taskbar - it's probably minimized.
  • Visual Studio performance profiling is currently unsupported for MSIX-packaged projects deployed using universal authentication.

Non-packaged C++ projects

  • When remote debugging non-packaged C++ projects in a debug configuration, the C++ runtime needs to be statically linked, or execution will fail. This isn't necessary for release configurations. This is found in your project's properties under C/C++ > Code Generation, or you can use the /MTd flag if you compile from a command line.
  • When remote debugging non-packaged C++ projects in a release configuration, you should either statically link the C++ runtime (/MT), or you will first need to install the latest Visual C++ Redistributable. Download and install this in the emulator before debugging.

C++ debug compiler setting