May 9, 2019 9:00 am

Windows 10 SDK Preview Build 18890 available now!

By / Program Manager, Windows Developer Team

Today, we released a new Windows 10 Preview Build of the SDK to be used in conjunction with Windows 10 Insider Preview (Build 18890 or greater). The Preview SDK Build 18890 contains bug fixes and under development changes to the API surface area.

The Preview SDK can be downloaded from the developer section on Windows Insider.

For feedback and updates to the known issues, please see the developer forum. For new developer feature requests, head over to our Windows Platform UserVoice.

Things to note:

  • This build works in conjunction with previously released SDKs and Visual Studio 2017 and 2019. You can install this SDK and still also continue to submit your apps that target Windows 10 build 1903 or earlier to the Microsoft Store.
  • The Windows SDK will now formally only be supported by Visual Studio 2017 and greater. You can download the Visual Studio 2019 here.
  • This build of the Windows SDK will install ONLY on Windows 10 Insider Preview builds.
  • In order to assist with script access to the SDK, the ISO will also be able to be accessed through the following static URL:

Tools Updates

Message Compiler (mc.exe)

  • Now detects the Unicode byte order mark (BOM) in .mc files. If the If the .mc file starts with a UTF-8 BOM, it will be read as a UTF-8 file. If it starts with a UTF-16LE BOM, it will be read as a UTF-16LE file. Otherwise, if the -u parameter was specified, it will be read as a UTF-16LE file. Otherwise, it will be read using the current code page (CP_ACP).
  • Now avoids one-definition-rule (ODR) problems in MC-generated C/C++ ETW helpers caused by conflicting configuration macros (e.g. when two .cpp files with conflicting definitions of MCGEN_EVENTWRITETRANSFER are linked into the same binary, the MC-generated ETW helpers will now respect the definition of MCGEN_EVENTWRITETRANSFER in each .cpp file instead of arbitrarily picking one or the other).

Windows Trace Preprocessor (tracewpp.exe)

  • Now supports Unicode input (.ini, .tpl, and source code) files. Input files starting with a UTF-8 or UTF-16 byte order mark (BOM) will be read as Unicode. Input files that do not start with a BOM will be read using the current code page (CP_ACP). For backwards-compatibility, if the -UnicodeIgnore command-line parameter is specified, files starting with a UTF-16 BOM will be treated as empty.
  • Now supports Unicode output (.tmh) files. By default, output files will be encoded using the current code page (CP_ACP). Use command-line parameters -cp:UTF-8 or -cp:UTF-16 to generate Unicode output files.
  • Behavior change: tracewpp now converts all input text to Unicode, performs processing in Unicode, and converts output text to the specified output encoding. Earlier versions of tracewpp avoided Unicode conversions and performed text processing assuming a single-byte character set. This may lead to behavior changes in cases where the input files do not conform to the current code page. In cases where this is a problem, consider converting the input files to UTF-8 (with BOM) and/or using the -cp:UTF-8 command-line parameter to avoid encoding ambiguity.


  • Now avoids one-definition-rule (ODR) problems caused by conflicting configuration macros (e.g. when two .cpp files with conflicting definitions of TLG_EVENT_WRITE_TRANSFER are linked into the same binary, the TraceLoggingProvider.h helpers will now respect the definition of TLG_EVENT_WRITE_TRANSFER in each .cpp file instead of arbitrarily picking one or the other).
  • In C++ code, the TraceLoggingWrite macro has been updated to enable better code sharing between similar events using variadic templates.

Breaking Changes

Removal of IRPROPS.LIB

In this release irprops.lib has been removed from the Windows SDK. Apps that were linking against irprops.lib can switch to bthprops.lib as a drop-in replacement.

API Updates, Additions and Removals

The following APIs have been added to the platform since the release of Windows 10 SDK, version 1903, build 18362.


namespace Windows.Foundation.Metadata {
  public sealed class AttributeNameAttribute : Attribute
  public sealed class FastAbiAttribute : Attribute
  public sealed class NoExceptionAttribute : Attribute
namespace Windows.UI.Composition.Particles {
  public sealed class ParticleAttractor : CompositionObject
  public sealed class ParticleAttractorCollection : CompositionObject, IIterable<ParticleAttractor>, IVector<ParticleAttractor>
  public class ParticleBaseBehavior : CompositionObject
  public sealed class ParticleBehaviors : CompositionObject
  public sealed class ParticleColorBehavior : ParticleBaseBehavior
  public struct ParticleColorBinding
  public sealed class ParticleColorBindingCollection : CompositionObject, IIterable<IKeyValuePair<float, ParticleColorBinding>>, IMap<float, ParticleColorBinding>
  public enum ParticleEmitFrom
  public sealed class ParticleEmitterVisual : ContainerVisual
  public sealed class ParticleGenerator : CompositionObject
  public enum ParticleInputSource
  public enum ParticleReferenceFrame
  public sealed class ParticleScalarBehavior : ParticleBaseBehavior
  public struct ParticleScalarBinding
  public sealed class ParticleScalarBindingCollection : CompositionObject, IIterable<IKeyValuePair<float, ParticleScalarBinding>>, IMap<float, ParticleScalarBinding>
  public enum ParticleSortMode
  public sealed class ParticleVector2Behavior : ParticleBaseBehavior
  public struct ParticleVector2Binding
  public sealed class ParticleVector2BindingCollection : CompositionObject, IIterable<IKeyValuePair<float, ParticleVector2Binding>>, IMap<float, ParticleVector2Binding>
  public sealed class ParticleVector3Behavior : ParticleBaseBehavior
  public struct ParticleVector3Binding
  public sealed class ParticleVector3BindingCollection : CompositionObject, IIterable<IKeyValuePair<float, ParticleVector3Binding>>, IMap<float, ParticleVector3Binding>
  public sealed class ParticleVector4Behavior : ParticleBaseBehavior
  public struct ParticleVector4Binding
  public sealed class ParticleVector4BindingCollection : CompositionObject, IIterable<IKeyValuePair<float, ParticleVector4Binding>>, IMap<float, ParticleVector4Binding>