Windows 10 SDK preview build 17040 now available for developers

Developers can now get their hands on Windows 10 SDK preview build 17040, Microsoft has announced. This latest release doesn't contain much in the way of changes, but it does contain some known issues to be aware of. This is the third Redstone 4 SDK preview build to hit developers, following the release of SDK preview builds 17025 and 17035.

Like the previous release, SDK preview 17040 includes the C++/WinRT headers and cppwinrt compiler, along with new MIDL key words. Here's a look at what's new, along with the known issues, and more.

What's New

  • C++/WinRT Now Available: The C++/WinRT headers and cppwinrt compiler (cppwinrt.exe) are now included in the Windows SDK. The compiler comes in handy if you need to consume a third-party WinRT component or if you need to author your own WinRT components with C++/WinRT. The easiest way to get working with it after installing the Windows Insider Preview SDK is to start the Visual Studio Developer Command Prompt and run the compiler in that environment. Authoring support is currently experimental and subject to change. Stay tuned as we will publish more detailed instructions on how to use the compiler in the coming week. The ModernCPP blog has a deeper dive into the CppWinRT compiler. Please give us feedback by creating an issue at:

Breaking Changes

  • New MIDL key words - As a part of the "modernizing IDL" effort, several new keywords are added to the midlrt tool. These new keywords will cause build breaks if they are encountered in IDL files. The new keywords are:
  • event
  • set
  • get
  • partial
  • unsealed
  • overridable
  • protected
  • importwinmd

Known Issues

  • "All tests run with Windows App Certification Kit will fail. During installation, please uncheck Windows App Certification Kit"
  • Installation on an operating system that is not a Windows 10 Insider Preview build is not supported and may fail.

The full list of API additions since the release of build 16299 can also be found in Microsoft's full release notes. SDK preview build 17040 is only supported by Visual Studio 2017, and it can be installed alongside previously released SDKs. If you're a developer, you can download the SDK preview release from Microsoft now.

Dan Thorp-Lancaster

Dan Thorp-Lancaster is the former Editor-in-Chief of Windows Central. He began working with Windows Central, Android Central, and iMore as a news writer in 2014 and is obsessed with tech of all sorts. You can follow Dan on Twitter @DthorpL and Instagram @heyitsdtl