`Microsoft.ui.xaml.dll` is unable to load

Question

I am getting an exception in my WinUI3 app that Microsoft.ui.xaml.dll is unable to load. I have included Microsoft.UI.Xaml and Microsoft.Graphics.Win2D in nuget.

System.DllNotFoundException
  HResult=0x80131524
  Message=Unable to load DLL 'Microsoft.ui.xaml.dll' or one of its dependencies: The specified module could not be found. (0x8007007E)
  Source=TibraUI
  StackTrace:
   at TibraUI.Program.XamlCheckProcessRequirements()
   at TibraUI.Program.Main(String[] args) in C:\Users\Bryan\src\tibra\Tibra\TibraUI\obj\x64\Debug\net6.0-windows10.0.19041.0\win10-x64\App.g.i.cs:line 28

Windows Version 21H1 Build 19043.1348

My App.xaml

<Application
    x:Class="TibraUI.App"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:TibraUI">
    <Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
                <!-- Other merged dictionaries here -->
            </ResourceDictionary.MergedDictionaries>
            <!-- Other app resources here -->
        </ResourceDictionary>
    </Application.Resources>
</Application>

Answer 1

Run the package as the startup project. It's not intuitive, but the main project is not meant to run.

This answer only applies to those who created a project that included a package project.

Answer 2

In the app project file, inside the main PropertyGroup, add <WindowsAppSDKSelfContained>true</WindowsAppSDKSelfContained> as shown below.

  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net6.0-windows10.0.19041.0</TargetFramework>
    <TargetPlatformMinVersion>10.0.17763.0</TargetPlatformMinVersion>
    <RootNamespace>EPicker</RootNamespace>
    <ApplicationManifest>app.manifest</ApplicationManifest>
    <Platforms>x86;x64;arm64</Platforms>
    <RuntimeIdentifiers>win10-x86;win10-x64;win10-arm64</RuntimeIdentifiers>
    <PublishProfile>win10-$(Platform).pubxml</PublishProfile>
    <UseWinUI>true</UseWinUI>
    <EnableMsixTooling>true</EnableMsixTooling>
    <WindowsAppSDKSelfContained>true</WindowsAppSDKSelfContained>
  </PropertyGroup>