Windows 10 SDK Preview Build 17692 released.

Things to note:

  • This build works in conjunction with previously released SDKs and Visual Studio 2017. You can install this SDK and still also continue to submit your apps that target Windows 10 build 1803 or earlier to the Store.
  • The Windows SDK will now formally only be supported by Visual Studio 2017 and greater.
  • This build of the Windows SDK will only install on Windows 10 Insider Preview.

What’s New:

MSIX Support

It’s finally here! You can now package your applications as MSIX! These applications can be installed and run on any device with 17682 build or later.

To package your application with MSIX, use the MakeAppx tool. To install the application – just click on the MSIX file.

MSIX is not currently supported by the App Certification Kit nor the Microsoft Store at this time.


We’ve made some important changes to the C/C++ ETW code generation of mc.exe (Message Compiler):

The “-mof” parameter is deprecated. This parameter instructs MC.exe to generate ETW code that is compatible with Windows XP and earlier. Support for the “-mof” parameter will be removed in a future version of mc.exe.

As long as the “-mof” parameter is not used, the generated C/C++ header is now compatible with both kernel-mode and user-mode, regardless of whether “-km” or “-um” was specified on the command line. The header will use the _ETW_KM_ macro to automatically determine whether it is being compiled for kernel-mode or user-mode and will call the appropriate ETW APIs for each mode.

  • The only remaining difference between “-km” and “-um” is that the EventWrite[EventName] macros generated with “-km” have an Activity ID parameter while the EventWrite[EventName] macros generated with “-um” do not have an Activity ID parameter.

The EventWrite[EventName] macros now default to calling EventWriteTransfer (user mode) or EtwWriteTransfer (kernel mode). Previously, the EventWrite[EventName] macros defaulted to calling EventWrite (user mode) or EtwWrite (kernel mode).

  • The generated header now supports several customization macros. For example, you can set the MCGEN_EVENTWRITETRANSFER macro if you need the generated macros to call something other than EventWriteTransfer.
  • The manifest supports new attributes.
    • Event “name”: non-localized event name.
    • Event “attributes”: additional key-value metadata for an event such as filename, line number, component name, function name.
    • Event “tags”: 28-bit value with user-defined semantics (per-event).
    • Field “tags”: 28-bit value with user-defined semantics (per-field – can be applied to “data” or “struct” elements).
  • You can now define “provider traits” in the manifest (e.g. provider group). If provider traits are used in the manifest, the EventRegister[ProviderName] macro will automatically register them.
  • MC will now report an error if a localized message file is missing a string. (Previously MC would silently generate a corrupt message resource.)
  • MC can now generate Unicode (utf-8 or utf-16) output with the “-cp utf-8” or “-cp utf-16” parameters.

Known Issues:

The SDK headers are generated with types in the “ABI” namespace. This is done to avoid conflicts with C++/CX and C++/WinRT clients that need to consume types directly at the ABI layer[1]. By default, types emitted by MIDL are *not* put in the ABI namespace, however this has the potential to introduce conflicts from teams attempting to consume ABI types from Windows WinRT MIDL generated headers and non-Windows WinRT MIDL generated headers (this is especially challenging if the non-Windows header references Windows types).

To ensure that developers have a consistent view of the WinRT API surface, validation has been added to the generated headers to ensure that the ABI prefix is consistent between the Windows headers and user generated headers. If you encounter an error like:

5>c:\program files (x86)\windows kits\10\include\10.0.17687.0\winrt\ error C2220: warning treated as error – no ‘object’ file generated
5>c:\program files (x86)\windows kits\10\include\10.0.17687.0\winrt\ warning C4005: ‘CHECK_NS_PREFIX_STATE’: macro redefinition
5>g:\<PATH TO YOUR HEADER HERE>(41): note: see previous definition of ‘CHECK_NS_PREFIX_STATE’

It means that some of your MIDL generated headers are inconsistent with the system generated headers.

There are two ways to fix this:

  • Preferred: Compile your IDL file with the /ns_prefix MIDL command line switch. This will cause all your types to be moved to the ABI namespace consistent with the Windows headers. This may require code changes in your code however.
  • Alternate: Add #define DISABLE_NS_PREFIX_CHECKS before including the Windows headers. This will suppress the validation.

API Spot Light:

Check out LauncherOptions.GroupingPreference.

namespace Windows.System {
  public sealed class FolderLauncherOptions : ILauncherViewOptions {
    ViewGrouping GroupingPreference { get; set; }
  public sealed class LauncherOptions : ILauncherViewOptions {
    ViewGrouping GroupingPreference { get; set; }

This release contains the new LauncherOptions.GroupingPreference property to assist your app in tailoring its behavior for Sets.

Read more about API Updates, Additions and Removals here.