无法在Visual Studio 2017中引用Windows IoT

当我将Visual Studio 2017升级到15.8.2时，它崩溃了，我不得不擦除所有内容并重新加载 . 从那时起，我无法获得UWP的Windows IoT扩展 . 当我单击项目中的引用时，Windows IoT扩展显示为黄色三角形 . 我右键单击引用添加引用，转到通用窗口（它显示核心和扩展），我单击扩展和Windows IoT不存在 . 我已经多次卸载并安装了VS2017，我认为我正在按照IoT的说明进行安装上的信件，但显然我很厚实并且缺少一些东西 . 任何帮助将不胜感激 .

<?xml version="1.0" encoding="utf-8"?>
<Package xmlns="http://schemas.microsoft.com/appx/manifest/foundation/windows10" xmlns:mp="http://schemas.microsoft.com/appx/2014/phone/manifest" xmlns:uap="http://schemas.microsoft.com/appx/manifest/uap/windows10" xmlns:iot="http://schemas.microsoft.com/appx/manifest/iot/windows10" IgnorableNamespaces="uap mp iot">
  <Identity Name="3ac96fd1-69de-454f-a811-1b1ac668e762" Publisher="CN=kbown" Version="1.0.0.0" />
  <mp:PhoneIdentity PhoneProductId="3ac96fd1-69de-454f-a811-1b1ac668e762" PhonePublisherId="00000000-0000-0000-0000-000000000000" />
  <Properties>
    <DisplayName>Water_Dewater</DisplayName>
    <PublisherDisplayName>kbown</PublisherDisplayName>
    <Logo>Assets\StoreLogo.png</Logo>
  </Properties>
  <Dependencies>
    <TargetDeviceFamily Name="Windows.Universal" MinVersion="10.0.0.0" MaxVersionTested="10.0.0.0" />
  </Dependencies>
  <Resources>
    <Resource Language="x-generate" />
  </Resources>
  <Applications>
    <Application Id="App" Executable="$targetnametoken$.exe"          EntryPoint="Water_Dewater.App">
      <uap:VisualElements DisplayName="Water_Dewater" Square150x150Logo="Assets\Square150x150Logo.png" Square44x44Logo="Assets\Square44x44Logo.png" Description="Water_Dewater" BackgroundColor="transparent">
        <uap:DefaultTile Wide310x150Logo="Assets\Wide310x150Logo.png">
        </uap:DefaultTile>
        <uap:SplashScreen Image="Assets\SplashScreen.png" />
      </uap:VisualElements>
    </Application>
  </Applications>
  <Capabilities>
    <Capability Name="internetClient" />
    <iot:Capability Name="lowLevelDevices" />
    <iot:Capability Name="systemManagement" />
    <DeviceCapability Name="109b86ad-f53d-4b76-aa5f-821e2ddf2141" />
  </Capabilities>
</Package>

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