Why is my Package.appxmanifest Extension giving me validation error C00CE014?

Question

In a new Visual Studio 2019 solution I have created a .Net Core Console Project and a UWP Project that I am packaging using a Windows Application Packaging Project. At this stage I am able to compile and run all of these projects without issue.

My next task is to add the compiled output of the console application as a windows.fullTrustProcess in the Package.appxmanifest for the packaging project:

<?xml version="1.0" encoding="utf-8"?>

<Package
  xmlns="http://schemas.microsoft.com/appx/manifest/foundation/windows10"
  xmlns:uap="http://schemas.microsoft.com/appx/manifest/uap/windows10"
  xmlns:uap3="http://schemas.microsoft.com/appx/manifest/uap/windows10/3"
  xmlns:desktop="http://schemas.microsoft.com/appx/manifest/desktop/windows10"
  xmlns:rescap="http://schemas.microsoft.com/appx/manifest/foundation/windows10/restrictedcapabilities"
  IgnorableNamespaces="uap uap3 desktop rescap">

  <Identity
    Name="7260053b-0cee-406a-a6ce-0842444e35eb"
    Publisher="CN=Publisher"
    Version="1.0.0.0" />

  <Properties>
    <DisplayName>DisplayName</DisplayName>
    <PublisherDisplayName>DisplayName</PublisherDisplayName>
    <Logo>Images\StoreLogo.png</Logo>
  </Properties>

  <Dependencies>
    <TargetDeviceFamily Name="Windows.Universal" MinVersion="10.0.0.0" MaxVersionTested="10.0.0.0" />
    <TargetDeviceFamily Name="Windows.Desktop" MinVersion="10.0.14393.0" MaxVersionTested="10.0.14393.0" />
  </Dependencies>

  <Resources>
    <Resource Language="x-generate"/>
  </Resources>

  <Applications>
    <Application Id="App"
      Executable="$targetnametoken$.exe"
      EntryPoint="$targetentrypoint$">
      <uap:VisualElements
        DisplayName="DisplayName"
        Description="Description"
        BackgroundColor="transparent"
        Square150x150Logo="Images\Square150x150Logo.png"
        Square44x44Logo="Images\Square44x44Logo.png">
        <uap:DefaultTile Wide310x150Logo="Images\Wide310x150Logo.png" />
        <uap:SplashScreen Image="Images\SplashScreen.png" />
      </uap:VisualElements>
    </Application>
  </Applications>

  <Capabilities>
    <Capability Name="internetClient" />
    <rescap:Capability Name="runFullTrust" />
    <rescap:Capability Name="allowElevation" />
  </Capabilities>

  <Extensions>
    <uap3:Extension Category="windows.fullTrustProcess" Executable="MyConsoleApp.exe"/>
  </Extensions>

</Package>

When I attempt to build the packaging project I get the following build error:

Error APPX0501: Validation error. error C00CE014: App manifest validation error: The app manifest must be valid as per schema: Line 40, Column 6, Reason: Element '{http://schemas.microsoft.com/appx/manifest/uap/windows10/3}Extension' is unexpected according to content model of parent element '{http://schemas.microsoft.com/appx/manifest/foundation/windows10}Extensions'. Expecting: {http://schemas.microsoft.com/appx/manifest/foundation/windows10}Extension, {http://schemas.microsoft.com/appx/manifest/foundation/windows10}ExtensionChoice.

I have tried different combinations of Extension, uap:Extension, desktop:Extension and they all give me similar errors. I believe fundamentally I don't understand enough about the appxmanifest namespaces to diagnose the problem.

How can I correctly declare my fullTrustProcess extension?

Answer 1

Please put the Extensions inside the Application block.

Like the following:

<Applications>
<Application Id="App" Executable="$targetnametoken$.exe" EntryPoint="$targetentrypoint$">
  <uap:VisualElements ....../>
  </uap:VisualElements>
  <Extensions>
    <desktop:Extension Category="windows.fullTrustProcess" Executable="FullTrust\FullTrust.exe" />
  </Extensions>
</Application>