I’m also having that problem, it’s caused by WWise. I’m taking a look at it and i’ll let you know if i find anything useful. Right now all i have is the log information:
UEBuildTarget.AddPlugin: Enabling plugin 'Wwise' (referenced via default plugins)
<>c.<PrintExceptionInfo>b__4_1: ==============================================================================
<>c.<PrintExceptionInfo>b__4_0: UnrealBuildTool: ERROR: Unable to expand variable in '$(DXSDK_DIR)\Lib\x64'
<>c.<PrintExceptionInfo>b__4_0: (see ../Programs/UnrealBuildTool/Log.txt for full exception trace)
<>c.<PrintExceptionInfo>b__4_1:
<>c.<PrintExceptionInfo>b__4_1: BuildException: Unable to expand variable in '$(DXSDK_DIR)\Lib\x64'
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildModule.CreateDirectoryHashSet(IEnumerable`1 InEnumerableStrings) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildModule.cs:line 259
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildModule..ctor(String InName, UHTModuleType InType, DirectoryReference InModuleDirectory, ModuleRules InRules, FileReference InRulesFile, List`1 InRuntimeDependencies) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildModule.cs:line 182
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildModuleCPP..ctor(String InName, UHTModuleType InType, DirectoryReference InModuleDirectory, DirectoryReference InIntermediateDirectory, DirectoryReference InGeneratedCodeDirectory, IEnumerable`1 InSourceFiles, ModuleRules InRules, Boolean bInBuildSourceFiles, FileReference InRulesFile, List`1 InRuntimeDependencies) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildModuleCPP.cs:line 286
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildTarget.InstantiateModule(ModuleRules RulesObject, String ModuleName, UHTModuleType ModuleType, DirectoryReference ModuleDirectory, DirectoryReference GeneratedCodeDirectory, List`1 ModuleSourceFiles, Boolean bBuildSourceFiles, FileReference InRulesFile, List`1 InRuntimeDependencies, PluginInfo Plugin) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildTarget.cs:line 4378
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildTarget.FindOrCreateModuleByName(String ModuleName, String ReferenceChain) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildTarget.cs:line 4340
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildTarget.FindOrCreateCppModuleByName(String ModuleName, String ReferenceChain) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildTarget.cs:line 4355
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildTarget.AddPlugin(PluginReferenceDescriptor Reference, String ReferenceChain, FileSystemName[] ExcludeFolders, Dictionary`2 NameToInstance, Dictionary`2 NameToInfo) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildTarget.cs:line 3582
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildTarget.SetupPlugins() in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildTarget.cs:line 3439
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildTarget.PreBuildSetup(UEToolChain TargetToolChain) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildTarget.cs:line 2622
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UEBuildTarget.Build(BuildConfiguration BuildConfiguration, CPPHeaders Headers, List`1 OutputItems, List`1 UObjectModules, ISourceFileWorkingSet WorkingSet, ActionGraph ActionGraph, EHotReload HotReload, Boolean bIsAssemblingBuild) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\Configuration\UEBuildTarget.cs:line 2021
<>c.<PrintExceptionInfo>b__4_1: at UnrealBuildTool.UnrealBuildTool.RunUBT(BuildConfiguration BuildConfiguration, String[] Arguments, FileReference ProjectFile, Boolean bCatchExceptions) in D:\Build\++UE4\Sync\Saved\CsTools\Engine\Source\Programs\UnrealBuildTool\UnrealBuildTool.cs:line 1480
<>c.<PrintExceptionInfo>b__4_1: ==============================================================================
Update 1:
The problem is in the AkAudio.Build.cs for WWise Plugin:
PublicLibraryPaths.Add("$(DXSDK_DIR)" + Path.DirectorySeparatorChar + “Lib” + Path.DirectorySeparatorChar + LibFolder);
My guess is that we are missing the DXSDK_DIR environment variable in Windows to set the path to the directx sdk folder. So i need to find where it is.