diff --git a/src/SamplesApp/UITests.Shared/Windows_Media/MediaPlayerTests.xaml b/src/SamplesApp/UITests.Shared/Windows_Media/MediaPlayerTests.xaml
index 97f7b5991fd0..c29790e1b529 100644
--- a/src/SamplesApp/UITests.Shared/Windows_Media/MediaPlayerTests.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_Media/MediaPlayerTests.xaml
@@ -3,13 +3,14 @@
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     xmlns:local="using:UITests.Windows_Media"
+	xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     xmlns:valueConverters="using:UITests.ValueConverters"
     mc:Ignorable="d"
     Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
 	<StackPanel>
-		<MediaPlayerElement x:Name="playbaby"
+		<not_mux:MediaPlayerElement x:Name="playbaby"
 		                    Source="{x:Bind ToMediaPlaybackItem(SoundToPlay)}"
 		                    AreTransportControlsEnabled="True"
 		                    Visibility="Visible"
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_3gp_Extension.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_3gp_Extension.xaml
index 131835adf3fb..9535939eb2dc 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_3gp_Extension.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_3gp_Extension.xaml
@@ -1,10 +1,11 @@
 <UserControl x:Class="UITests.Shared.Windows_UI_Xaml_Controls.MediaPlayerElement.MediaPlayerElement_3gp_Extension"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              mc:Ignorable="">
 
-    <MediaPlayerElement Source="http://mirrors.standaloneinstaller.com/video-sample/jellyfish-25-mbps-hd-hevc.3gp"
+	<not_mux:MediaPlayerElement Source="http://mirrors.standaloneinstaller.com/video-sample/jellyfish-25-mbps-hd-hevc.3gp"
 						AreTransportControlsEnabled="True"
 						AutoPlay="True" />
 </UserControl>
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Avi_Extension.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Avi_Extension.xaml
index d65409c309fb..3ba04a544772 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Avi_Extension.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Avi_Extension.xaml
@@ -1,10 +1,11 @@
 <UserControl x:Class="UITests.Shared.Windows_UI_Xaml_Controls.MediaPlayerElement.MediaPlayerElement_Avi_Extension"
 			 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 			 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 			 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 			 mc:Ignorable="">
 
-	<MediaPlayerElement Source="http://mirrors.standaloneinstaller.com/video-sample/Panasonic_HDC_TM_700_P_50i.avi"
+	<not_mux:MediaPlayerElement Source="http://mirrors.standaloneinstaller.com/video-sample/Panasonic_HDC_TM_700_P_50i.avi"
 						AreTransportControlsEnabled="True"
 						AutoPlay="True" />
 </UserControl>
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Flv_Extension.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Flv_Extension.xaml
index 2744e25804eb..068c949d235b 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Flv_Extension.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Flv_Extension.xaml
@@ -1,10 +1,11 @@
 <UserControl x:Class="UITests.Shared.Windows_UI_Xaml_Controls.MediaPlayerElement.MediaPlayerElement_Flv_Extension"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              mc:Ignorable="">
 
-    <MediaPlayerElement Source="https://sample-videos.com/video123/flv/360/big_buck_bunny_360p_5mb.flv"
+	<not_mux:MediaPlayerElement Source="https://sample-videos.com/video123/flv/360/big_buck_bunny_360p_5mb.flv"
 						AreTransportControlsEnabled="True"
 						AutoPlay="True" />
 </UserControl>
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Full.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Full.xaml
index 23ee5397881d..efb46cae8e00 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Full.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Full.xaml
@@ -1,6 +1,7 @@
 <UserControl x:Class="UITests.Shared.Windows_UI_Xaml_Controls.MediaPlayerElement.MediaPlayerElement_Full"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
-             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+ 			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+            xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
 
     <Grid>
 		<Grid.RowDefinitions>
@@ -8,7 +9,7 @@
 			<RowDefinition Height="2*" />
 		</Grid.RowDefinitions>
 
-		<MediaPlayerElement x:Name="Mpe"
+		<not_mux:MediaPlayerElement x:Name="Mpe"
 							Source="https://bitmovin-a.akamaihd.net/content/sintel/hls/playlist.m3u8"
 							PosterSource="https://bitmovin-a.akamaihd.net/content/sintel/poster.png"
 							AreTransportControlsEnabled="{Binding IsChecked, ElementName=AreTransportControlsEnabled}"
@@ -41,7 +42,7 @@
 										IsZoomButtonVisible="{Binding IsChecked, ElementName=IsZoomButtonVisible}"
 										IsZoomEnabled="{Binding IsChecked, ElementName=IsZoomEnabled}" />
 			</MediaPlayerElement.TransportControls>
-		</MediaPlayerElement>
+		</not_mux:MediaPlayerElement>
 
 		<ScrollViewer Grid.Row="1"
 					  Margin="10,20">
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Minimal.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Minimal.xaml
index 119c0cf44492..e5c865336d77 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Minimal.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Minimal.xaml
@@ -1,10 +1,11 @@
 <UserControl x:Class="UITests.Shared.Windows_UI_Xaml_Controls.MediaPlayerElement.MediaPlayerElement_Minimal"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
 
 	<UserControl.Resources>
 
-		<Style TargetType="MediaTransportControls"
+		<not_mux:Style TargetType="MediaTransportControls"
 			   x:Key="MediaTransportControlsMinimalStyle">
 			<Setter Property="IsTabStop"
 					Value="False" />
@@ -125,17 +126,17 @@
 					</ControlTemplate>
 				</Setter.Value>
 			</Setter>
-		</Style>
+		</not_mux:Style>
 		
 	</UserControl.Resources>
 
-	<MediaPlayerElement Source="https://bitmovin-a.akamaihd.net/content/sintel/hls/playlist.m3u8"
+	<not_mux:MediaPlayerElement Source="https://bitmovin-a.akamaihd.net/content/sintel/hls/playlist.m3u8"
 						PosterSource="https://bitmovin-a.akamaihd.net/content/sintel/poster.png"
 						AreTransportControlsEnabled="True"
 						AutoPlay="True">
 		<MediaPlayerElement.TransportControls>
 			<MediaTransportControls Style="{StaticResource MediaTransportControlsMinimalStyle}" />
 		</MediaPlayerElement.TransportControls>
-	</MediaPlayerElement>
+	</not_mux:MediaPlayerElement>
 	
 </UserControl>
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Mkv_Extension.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Mkv_Extension.xaml
index 139e3a4da0d0..197f4859cb7e 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Mkv_Extension.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Mkv_Extension.xaml
@@ -1,10 +1,11 @@
 <UserControl x:Class="UITests.Shared.Windows_UI_Xaml_Controls.MediaPlayerElement.MediaPlayerElement_Mkv_Extension"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              mc:Ignorable="">
 
-    <MediaPlayerElement Source="https://sample-videos.com/video123/mkv/720/big_buck_bunny_720p_5mb.mkv"
+	<not_mux:MediaPlayerElement Source="https://sample-videos.com/video123/mkv/720/big_buck_bunny_720p_5mb.mkv"
 						AreTransportControlsEnabled="True"
 						AutoPlay="True" />
 </UserControl>
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Mov_Extension.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Mov_Extension.xaml
index 16647b4e9e31..61f9a02a893e 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Mov_Extension.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Mov_Extension.xaml
@@ -1,10 +1,11 @@
 <UserControl x:Class="UITests.Shared.Windows_UI_Xaml_Controls.MediaPlayerElement.MediaPlayerElement_Mov_Extension"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              mc:Ignorable="">
 
-    <MediaPlayerElement Source="http://file-examples.com/wp-content/uploads/2018/04/file_example_MOV_1280_1_4MB.mov"
+	<not_mux:MediaPlayerElement Source="http://file-examples.com/wp-content/uploads/2018/04/file_example_MOV_1280_1_4MB.mov"
 						AreTransportControlsEnabled="True"
 						AutoPlay="True" />
 </UserControl>
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Ogg_Extension.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Ogg_Extension.xaml
index 26bd6dd192b1..6e6903b38736 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Ogg_Extension.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Ogg_Extension.xaml
@@ -1,10 +1,11 @@
 <UserControl x:Class="UITests.Shared.Windows_UI_Xaml_Controls.MediaPlayerElement.MediaPlayerElement_Ogg_Extension"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              mc:Ignorable="">
 
-    <MediaPlayerElement Source="http://file-examples.com/wp-content/uploads/2018/04/file_example_OGG_640_2_7mg.ogg"
+	<not_mux:MediaPlayerElement Source="http://file-examples.com/wp-content/uploads/2018/04/file_example_OGG_640_2_7mg.ogg"
 						AreTransportControlsEnabled="True"
 						AutoPlay="True" />
 </UserControl>
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Original.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Original.xaml
index 8e232155ca25..0d4e9a3e63b5 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Original.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Original.xaml
@@ -1,10 +1,11 @@
 <UserControl x:Class="UITests.Shared.Windows_UI_Xaml_Controls.MediaPlayerElement.MediaPlayerElement_Original"
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              mc:Ignorable="">
 
-    <MediaPlayerElement Source="http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_30fps_normal.mp4"
+	<not_mux:MediaPlayerElement Source="http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_30fps_normal.mp4"
 						AreTransportControlsEnabled="True"
 						AutoPlay="True" />
 </UserControl>
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Sources.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Sources.xaml
index 6a5ba9c396b1..9e942e9a2e27 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Sources.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Sources.xaml
@@ -2,6 +2,7 @@
 			 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 			 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 			 xmlns:local="using:UITests.Windows_UI_Xaml_Controls.MediaPlayerElement"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 			 xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
 			 xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
 			 mc:Ignorable="d"
@@ -22,7 +23,7 @@
 				<ColumnDefinition Width="Auto" />
 			</Grid.ColumnDefinitions>
 
-			<MediaPlayerElement x:Name="Mpe"
+			<not_mux:MediaPlayerElement x:Name="Mpe"
 								AreTransportControlsEnabled="True"
 								AutoPlay="True"
 								Grid.ColumnSpan="2" />
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Sources.xaml.cs b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Sources.xaml.cs
index a5e885860f17..b5c22874a4e4 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Sources.xaml.cs
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Sources.xaml.cs
@@ -29,6 +29,7 @@ public MediaPlayerElement_Sources()
 
 		private void UpdateButton_Click(object sender, RoutedEventArgs e)
 		{
+#if !HAS_UNO_WINUI
 			var uri = SourceTextBox.Text;
 
 			if (!string.IsNullOrEmpty(uri))
@@ -39,6 +40,7 @@ private void UpdateButton_Click(object sender, RoutedEventArgs e)
 			{
 				Mpe.Source = null;
 			}
+#endif
 		}
 	}
 }
diff --git a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Stretch_Fill.xaml b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Stretch_Fill.xaml
index 4da7b4fe6223..6679b4b84fca 100644
--- a/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Stretch_Fill.xaml
+++ b/src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/MediaPlayerElement/MediaPlayerElement_Stretch_Fill.xaml
@@ -2,9 +2,10 @@
              xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+			 xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
              mc:Ignorable="">
 
-	<MediaPlayerElement Source="http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_30fps_normal.mp4"
+	<not_mux:MediaPlayerElement Source="http://distribution.bbb3d.renderfarming.net/video/mp4/bbb_sunflower_1080p_30fps_normal.mp4"
 						Stretch="Fill"
 						AreTransportControlsEnabled="True"
 						AutoPlay="True" />
diff --git a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-arm64.pubxml b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-arm64.pubxml
index f8763fd5f51c..c2f2c73110af 100644
--- a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-arm64.pubxml
+++ b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-arm64.pubxml
@@ -4,13 +4,16 @@ https://go.microsoft.com/fwlink/?LinkID=208121.
 -->
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
-    <PublishProtocol>FileSystem</PublishProtocol>
-    <Platform>arm64</Platform>
-    <RuntimeIdentifier>win10-arm64</RuntimeIdentifier>
-    <PublishDir>bin\$(Configuration)\$(TargetFramework)\$(RuntimeIdentifier)\publish\</PublishDir>
-    <SelfContained>true</SelfContained>
-    <PublishSingleFile>False</PublishSingleFile>
-    <PublishReadyToRun>True</PublishReadyToRun>
+	<PublishProtocol>FileSystem</PublishProtocol>
+	<Platform>arm64</Platform>
+	<RuntimeIdentifier>win10-arm64</RuntimeIdentifier>
+	<PublishDir>bin\$(Configuration)\$(TargetFramework)\$(RuntimeIdentifier)\publish\</PublishDir>
+	<SelfContained>true</SelfContained>
+	<PublishSingleFile>False</PublishSingleFile>
+	<PublishReadyToRun>True</PublishReadyToRun>
+	<!-- 
+    See https://github.com/microsoft/CsWinRT/issues/373
     <PublishTrimmed>True</PublishTrimmed>
+    -->
   </PropertyGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-x64.pubxml b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-x64.pubxml
index 9341269df3c7..d04e723ca30f 100644
--- a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-x64.pubxml
+++ b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-x64.pubxml
@@ -4,13 +4,16 @@ https://go.microsoft.com/fwlink/?LinkID=208121.
 -->
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
-    <PublishProtocol>FileSystem</PublishProtocol>
-    <Platform>x64</Platform>
-    <RuntimeIdentifier>win10-x64</RuntimeIdentifier>
-    <PublishDir>bin\$(Configuration)\$(TargetFramework)\$(RuntimeIdentifier)\publish\</PublishDir>
-    <SelfContained>true</SelfContained>
-    <PublishSingleFile>False</PublishSingleFile>
-    <PublishReadyToRun>True</PublishReadyToRun>
+	<PublishProtocol>FileSystem</PublishProtocol>
+	<Platform>x64</Platform>
+	<RuntimeIdentifier>win10-x64</RuntimeIdentifier>
+	<PublishDir>bin\$(Configuration)\$(TargetFramework)\$(RuntimeIdentifier)\publish\</PublishDir>
+	<SelfContained>true</SelfContained>
+	<PublishSingleFile>False</PublishSingleFile>
+	<PublishReadyToRun>True</PublishReadyToRun>
+	<!-- 
+    See https://github.com/microsoft/CsWinRT/issues/373
     <PublishTrimmed>True</PublishTrimmed>
+    -->
   </PropertyGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-x86.pubxml b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-x86.pubxml
index 6ec2ebadf523..6bcf3bb29bc4 100644
--- a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-x86.pubxml
+++ b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/Properties/PublishProfiles/win10-x86.pubxml
@@ -4,13 +4,16 @@ https://go.microsoft.com/fwlink/?LinkID=208121.
 -->
 <Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
-    <PublishProtocol>FileSystem</PublishProtocol>
-    <Platform>x86</Platform>
-    <RuntimeIdentifier>win10-x86</RuntimeIdentifier>
-    <PublishDir>bin\$(Configuration)\$(TargetFramework)\$(RuntimeIdentifier)\publish\</PublishDir>
-    <SelfContained>true</SelfContained>
-    <PublishSingleFile>False</PublishSingleFile>
-    <PublishReadyToRun>True</PublishReadyToRun>
+	<PublishProtocol>FileSystem</PublishProtocol>
+	<Platform>x86</Platform>
+	<RuntimeIdentifier>win10-x86</RuntimeIdentifier>
+	<PublishDir>bin\$(Configuration)\$(TargetFramework)\$(RuntimeIdentifier)\publish\</PublishDir>
+	<SelfContained>true</SelfContained>
+	<PublishSingleFile>False</PublishSingleFile>
+	<PublishReadyToRun>True</PublishReadyToRun>
+	<!-- 
+    See https://github.com/microsoft/CsWinRT/issues/373
     <PublishTrimmed>True</PublishTrimmed>
+    -->
   </PropertyGroup>
-</Project>
\ No newline at end of file
+</Project>
diff --git a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/UnoWinUIQuickStart.Windows.Desktop.csproj b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/UnoWinUIQuickStart.Windows.Desktop.csproj
index 6c32746c74c8..24a631d9b65d 100644
--- a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/UnoWinUIQuickStart.Windows.Desktop.csproj
+++ b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Desktop/UnoWinUIQuickStart.Windows.Desktop.csproj
@@ -11,11 +11,11 @@
 
 	<ItemGroup>
 		<PackageReference Include="Microsoft.VCRTForwarders.140" Version="1.0.6" />
-		<PackageReference Include="Microsoft.WinUI" Version="3.0.0-preview3.201113.0" />
+		<PackageReference Include="Microsoft.WinUI" Version="3.0.0-preview4.210210.4" />
 		<Manifest Include="$(ApplicationManifest)" />
 		<PackageReference Include="Microsoft.Extensions.Logging.Console" Version="1.1.1" />
 		<PackageReference Include="Microsoft.Extensions.Logging.Filter" Version="1.1.1" />
-		<PackageReference Include="Uno.Core" Version="2.0.0" />
+		<PackageReference Include="Uno.Core" Version="2.2.0" />
 	</ItemGroup>
 
 	<Import Project="..\UnoWinUIQuickStart.Shared\UnoWinUIQuickStart.Shared.projitems" Label="Shared" />
diff --git a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Package/UnoWinUIQuickStart.Windows.Package.wapproj b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Package/UnoWinUIQuickStart.Windows.Package.wapproj
index 7208fe4c4aa8..3a49338d1c7f 100644
--- a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Package/UnoWinUIQuickStart.Windows.Package.wapproj
+++ b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Package/UnoWinUIQuickStart.Windows.Package.wapproj
@@ -63,11 +63,6 @@
 	  <PublishProfile>Properties\PublishProfiles\win10-$(Platform).pubxml</PublishProfile>
 	</ProjectReference>
   </ItemGroup>
-  <ItemGroup>
-	<SDKReference Include="Microsoft.VCLibs.Desktop, Version=14.0" />
-	<!-- Needed for ucrtbased.dll when running a debug build. -->
-	<SDKReference Include="Microsoft.VCLibs, Version=14.0" Condition="'$(Configuration)' == 'Debug'" />
-  </ItemGroup>
   <Import Project="$(WapProjPath)\Microsoft.DesktopBridge.targets" />
   <Import Project="$(AppxTargetsLocation)Microsoft.WinUI.AppX.targets" />
 </Project>
diff --git a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Package/build/Microsoft.WinUI.AppX.targets b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Package/build/Microsoft.WinUI.AppX.targets
index e72ab35c59a2..40bf52e40f2a 100644
--- a/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Package/build/Microsoft.WinUI.AppX.targets
+++ b/src/SolutionTemplate/Uno.ProjectTemplates.Dotnet/content/unoapp-winui/UnoWinUIQuickStart.Windows.Package/build/Microsoft.WinUI.AppX.targets
@@ -207,20 +207,23 @@
   </Target>
 
   <!--
-    Add a dependency for the app against VCLibs since it doesn't come with .NET only apps. C++ apps
-    will already have this dependency, but duplicate referenes are a no-op so there's no need to
-    condition the dependency.
-   -->
-  <ItemGroup Condition="'$(OutputType)' == 'AppContainerExe'">
-    <SDKReference Include="Microsoft.VCLibs, Version=14.0" />
-  </ItemGroup>
-
-  <!-- Packaged desktop apps need these framework package references -->
-  <ItemGroup Condition="'$(MSBuildProjectExtension)'=='.wapproj'">
+    Add a dependency for the app against VCLibs.Desktop, which contains the CRT DLLs that WinUI 3 is linked against. -->
+  <ItemGroup Condition="'$(OutputType)' == 'Exe' or '$(OutputType)' == 'AppContainerExe' or '$(MSBuildProjectExtension)'=='.wapproj'">
     <SDKReference Include="Microsoft.VCLibs.Desktop, Version=14.0" />
     <!-- Needed for ucrtbased.dll when running a debug build. -->
-    <SDKReference Include="Microsoft.VCLibs, Version=14.0" Condition="'$(Configuration)' == 'Debug'" />
+    <SDKReference Include="Microsoft.UniversalCRT.Debug, Version=$(TargetPlatformVersion)" Condition="'$(Configuration)' == 'Debug'" />
+    <!-- Needed until Microsoft.ApplicationModel.Resources.dll and Microsoft.Web.WebView2.Core.dll
+         no longer depend on the _app version of CRT DLLs. -->
+    <SDKReference Include="Microsoft.VCLibs, Version=14.0" />
   </ItemGroup>
+  
+  <!-- In order to have the Microsoft.UniversalCRT.Debug SDK reference included in the AppX, we need to
+       set IncludeSDKRedistOutputGroup to true. -->
+  <Target Name="IncludeSDKRedistOutputGroup" BeforeTargets="GetPackagingOutputs" Condition="('$(OutputType)' == 'AppContainerExe' or '$(MSBuildProjectExtension)'=='.wapproj') and '$(Configuration)' == 'Debug'">
+    <PropertyGroup>
+      <IncludeSDKRedistOutputGroup>true</IncludeSDKRedistOutputGroup>
+    </PropertyGroup>
+  </Target>
 
   <!--
     WindowsAppContainer is the property that you can set in your .NET Desktop project to turn it into a UWP.
@@ -234,4 +237,16 @@
       </ProjectReferenceWithExtraMetadata>
     </ItemGroup>
   </Target>
+  
+  <!-- NuGet restore is now supported for wapproj files, so we need to supply an AssetTargetFallback value
+       in order for that not to raise an error. -->
+  <PropertyGroup Condition="'$(MSBuildProjectExtension)' == '.wapproj'">
+    <AssetTargetFallback>net5.0-windows$(TargetPlatformVersion)</AssetTargetFallback>
+  </PropertyGroup>
+
+  <!-- See https://github.com/microsoft/CsWinRT/issues/373 -->
+  <Target Name="ValidateNoPublishTrimmed" BeforeTargets="PrepareForBuild" Condition="'$(PublishTrimmed)'=='true'">
+    <Error Text="Publishing with IL trimming is not yet supported."/>
+  </Target>
+
 </Project>
diff --git a/src/Uno.UI.FluentTheme/Resources/PriorityDefault/MediaTransportControls_themeresources.xaml b/src/Uno.UI.FluentTheme/Resources/PriorityDefault/MediaTransportControls_themeresources.xaml
index 937512d85b79..c9c6eae6a3e4 100644
--- a/src/Uno.UI.FluentTheme/Resources/PriorityDefault/MediaTransportControls_themeresources.xaml
+++ b/src/Uno.UI.FluentTheme/Resources/PriorityDefault/MediaTransportControls_themeresources.xaml
@@ -1,6 +1,7 @@
 <!-- Copyright (c) Microsoft Corporation. All Rights Reserved. -->
 <ResourceDictionary
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+	xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
     <ResourceDictionary.ThemeDictionaries>
         <ResourceDictionary x:Key="Default">
@@ -20,9 +21,9 @@
         </ResourceDictionary>
     </ResourceDictionary.ThemeDictionaries>
 
-    <Style TargetType="MediaTransportControls" BasedOn="{StaticResource DefaultMediaTransportControlsStyle}" />
+	<not_mux:Style TargetType="MediaTransportControls" BasedOn="{StaticResource DefaultMediaTransportControlsStyle}" />
 
-    <Style x:Key="DefaultMediaTransportControlsStyle" TargetType="MediaTransportControls">
+	<not_mux:Style x:Key="DefaultMediaTransportControlsStyle" TargetType="MediaTransportControls">
         <Setter Property="IsTabStop" Value="False" />
         <Setter Property="Background" Value="Transparent" />
         <Setter Property="FlowDirection" Value="LeftToRight" />
@@ -877,5 +878,5 @@
                 </ControlTemplate>
             </Setter.Value>
         </Setter>
-    </Style>
+    </not_mux:Style>
 </ResourceDictionary>
diff --git a/src/Uno.UI.FluentTheme/themeresources.xaml b/src/Uno.UI.FluentTheme/themeresources.xaml
index 117b08b4c410..d47a73cd3b2f 100644
--- a/src/Uno.UI.FluentTheme/themeresources.xaml
+++ b/src/Uno.UI.FluentTheme/themeresources.xaml
@@ -1,4 +1,4 @@
-<ResourceDictionary xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:media="using:Microsoft.UI.Xaml.Media" xmlns:controls="using:Microsoft.UI.Xaml.Controls" xmlns:primitives="using:Microsoft.UI.Xaml.Controls.Primitives" xmlns:contract4Present="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractPresent(Windows.Foundation.UniversalApiContract,4)" xmlns:contract7Present="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractPresent(Windows.Foundation.UniversalApiContract,7)" xmlns:contract7NotPresent="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractNotPresent(Windows.Foundation.UniversalApiContract,7)" xmlns:primitiveContract7Present="using:Microsoft.UI.Xaml.Controls.Primitives?IsApiContractPresent(Windows.Foundation.UniversalApiContract,7)" xmlns:contract4NotPresent="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractNotPresent(Windows.Foundation.UniversalApiContract,4)" xmlns:wasm="http://uno.ui/wasm" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:unouwp="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractNotPresent(Uno.WinUI,1)" xmlns:win="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:contract6Present="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractPresent(Windows.Foundation.UniversalApiContract,6)" xmlns:uno="using:Uno.UI.Xaml.Controls" xmlns:ios="http://platform.uno/ios" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
+<ResourceDictionary xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:media="using:Microsoft.UI.Xaml.Media" xmlns:controls="using:Microsoft.UI.Xaml.Controls" xmlns:primitives="using:Microsoft.UI.Xaml.Controls.Primitives" xmlns:not_mux="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:contract4Present="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractPresent(Windows.Foundation.UniversalApiContract,4)" xmlns:contract7Present="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractPresent(Windows.Foundation.UniversalApiContract,7)" xmlns:contract7NotPresent="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractNotPresent(Windows.Foundation.UniversalApiContract,7)" xmlns:primitiveContract7Present="using:Microsoft.UI.Xaml.Controls.Primitives?IsApiContractPresent(Windows.Foundation.UniversalApiContract,7)" xmlns:contract4NotPresent="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractNotPresent(Windows.Foundation.UniversalApiContract,4)" xmlns:wasm="http://uno.ui/wasm" xmlns:d="http://schemas.microsoft.com/expression/blend/2008" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:unouwp="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractNotPresent(Uno.WinUI,1)" xmlns:contract6Present="http://schemas.microsoft.com/winfx/2006/xaml/presentation?IsApiContractPresent(Windows.Foundation.UniversalApiContract,6)" xmlns:uno="using:Uno.UI.Xaml.Controls" xmlns:ios="http://platform.uno/ios" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
   <ResourceDictionary.ThemeDictionaries>
     <ResourceDictionary x:Key="Default">
       <SolidColorBrush x:Key="SystemControlTransparentBrush" Color="Transparent" />
@@ -14854,8 +14854,8 @@
       </Setter.Value>
     </Setter>
   </Style>
-  <Style TargetType="MediaTransportControls" BasedOn="{StaticResource DefaultMediaTransportControlsStyle}" />
-  <Style x:Key="DefaultMediaTransportControlsStyle" TargetType="MediaTransportControls">
+  <not_mux:Style TargetType="MediaTransportControls" BasedOn="{StaticResource DefaultMediaTransportControlsStyle}" />
+  <not_mux:Style x:Key="DefaultMediaTransportControlsStyle" TargetType="MediaTransportControls">
     <Setter Property="IsTabStop" Value="False" />
     <Setter Property="Background" Value="Transparent" />
     <Setter Property="FlowDirection" Value="LeftToRight" />
@@ -15634,7 +15634,7 @@
         </ControlTemplate>
       </Setter.Value>
     </Setter>
-  </Style>
+  </not_mux:Style>
   <Style TargetType="controls:MenuBar" BasedOn="{StaticResource DefaultMenuBarStyle}" />
   <Style x:Key="DefaultMenuBarStyle" TargetType="controls:MenuBar">
     <Setter Property="Background" Value="{ThemeResource MenuBarBackground}" />
@@ -18459,7 +18459,7 @@
     <!-- UNO TODO: Doesn't appear in ScrollViewer because default visual states are incompatible with Uno fixed-orientation optimizations
              for performance. As of WinUI 2.5, seems visually very similar to previous ScrollBar template anyway. If this is restored, the 
              modifications made to the base UWP style on performance grounds should also be made here. -->
-    <win:Setter Property="Template">
+    <win:Setter Property="Template" xmlns:win="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
       <Setter.Value>
         <ControlTemplate TargetType="ScrollBar">
           <Grid x:Name="Root">
@@ -19416,7 +19416,7 @@
     <Setter Property="CompactPaneLength" Value="{ThemeResource SplitViewCompactPaneThemeLength}" />
     <Setter Property="PaneBackground" Value="{ThemeResource SystemControlPageBackgroundChromeLowBrush}" />
     <!--UNO TODO Fails to display correctly for multiple reasons, including https://github.com/unoplatform/uno/issues/325 but also undiagnosed issues -->
-    <win:Setter Property="Template">
+    <win:Setter Property="Template" xmlns:win="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
       <Setter.Value>
         <ControlTemplate TargetType="SplitView">
           <Grid Background="{TemplateBinding Background}">
@@ -20620,7 +20620,7 @@
       </Setter.Value>
     </Setter>
   </Style>
-  <win:Style TargetType="TimePickerFlyoutPresenter">
+  <win:Style TargetType="TimePickerFlyoutPresenter" xmlns:win="http://schemas.microsoft.com/winfx/2006/xaml/presentation">
     <Setter Property="Width" Value="242" />
     <Setter Property="MinWidth" Value="242" />
     <Setter Property="MaxHeight" Value="398" />
diff --git a/src/Uno.UI.Tests/Windows_UI_Xaml/Given_Implicit_Style.cs b/src/Uno.UI.Tests/Windows_UI_Xaml/Given_Implicit_Style.cs
index e6161388e1fb..d416658cd44c 100644
--- a/src/Uno.UI.Tests/Windows_UI_Xaml/Given_Implicit_Style.cs
+++ b/src/Uno.UI.Tests/Windows_UI_Xaml/Given_Implicit_Style.cs
@@ -238,8 +238,10 @@ public void Verify_Framework_DefaultStyleKeys()
 			AssertDefaultStyleKey<Windows.UI.Xaml.Controls.Primitives.PivotHeaderItem>();
 #endif
 			AssertDefaultStyleKey<Windows.UI.Xaml.Controls.AutoSuggestBox>();
+#if !HAS_UNO_WINUI
 			AssertDefaultStyleKey<Windows.UI.Xaml.Controls.MediaPlayerElement>();
 			AssertDefaultStyleKey<Windows.UI.Xaml.Controls.MediaTransportControls>();
+#endif
 			AssertDefaultStyleKey<Windows.UI.Xaml.Controls.Button>();
 			AssertDefaultStyleKey<Windows.UI.Xaml.Controls.CheckBox>();
 			AssertDefaultStyleKey<Windows.UI.Xaml.Controls.ToggleSwitch>();
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/Expander/ExpanderCollapsedEventArgs.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/Expander/ExpanderCollapsedEventArgs.cs
index 751d5f8d22c0..a6119dfbebdf 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/Expander/ExpanderCollapsedEventArgs.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/Expander/ExpanderCollapsedEventArgs.cs
@@ -6,7 +6,7 @@
 
 namespace Microsoft.UI.Xaml.Controls
 {
-	public class ExpanderCollapsedEventArgs : EventArgs
+	public partial class ExpanderCollapsedEventArgs : EventArgs
 	{
 	}
 }
diff --git a/src/Uno.UI/Microsoft/UI/Xaml/Controls/Expander/ExpanderExpandingEventArgs.cs b/src/Uno.UI/Microsoft/UI/Xaml/Controls/Expander/ExpanderExpandingEventArgs.cs
index 9ab9fadad255..649414e0105a 100644
--- a/src/Uno.UI/Microsoft/UI/Xaml/Controls/Expander/ExpanderExpandingEventArgs.cs
+++ b/src/Uno.UI/Microsoft/UI/Xaml/Controls/Expander/ExpanderExpandingEventArgs.cs
@@ -6,7 +6,7 @@
 
 namespace Microsoft.UI.Xaml.Controls
 {
-	public class ExpanderExpandingEventArgs : EventArgs
+	public partial class ExpanderExpandingEventArgs : EventArgs
 	{
 	}
 }
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerElement.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerElement.cs
index 39b645f4b821..f558fd7d95b1 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerElement.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerElement.cs
@@ -1,4 +1,4 @@
-#if __IOS__ || __ANDROID__ || __MACOS__
+#if !HAS_UNO_WINUI && (__IOS__ || __ANDROID__ || __MACOS__)
 using System;
 using Uno.Extensions;
 using Windows.Media.Playback;
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerElement.net.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerElement.net.cs
index 36da5c7b97d8..1278c97566f4 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerElement.net.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerElement.net.cs
@@ -1,4 +1,5 @@
-using System;
+#if !HAS_UNO_WINUI
+using System;
 using System.Collections.Generic;
 using System.Text;
 
@@ -12,3 +13,4 @@ public MediaPlayerElement()
 		}
     }
 }
+#endif
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.Android.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.Android.cs
index 19d1591e2fb6..ef5861d8676b 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.Android.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.Android.cs
@@ -1,3 +1,4 @@
+#if !HAS_UNO_WINUI
 using System;
 using Android.Views;
 using Uno.Media.Playback;
@@ -49,3 +50,4 @@ internal void ApplyStretch()
 		}
 	}
 }
+#endif
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.Others.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.Others.cs
index d9cb1c96ffff..95eb811f190e 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.Others.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.Others.cs
@@ -1,4 +1,4 @@
-#if !__ANDROID__ && !__IOS__ && !__MACOS__
+#if !HAS_UNO_WINUI && !__ANDROID__ && !__IOS__ && !__MACOS__
 using System;
 using Windows.Foundation;
 using Windows.Media.Playback;
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.cs
index 380eb0b5457f..18ca09669788 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.cs
@@ -1,4 +1,4 @@
-#if __ANDROID__ || __IOS__ || __MACOS__
+#if !HAS_UNO_WINUI && (__ANDROID__ || __IOS__ || __MACOS__)
 using System;
 using Windows.Foundation;
 using Windows.Media.Playback;
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.iOSmacOS.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.iOSmacOS.cs
index d53826b22f48..c4ed95c41ac5 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.iOSmacOS.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaPlayerPresenter.iOSmacOS.cs
@@ -1,3 +1,4 @@
+#if !HAS_UNO_WINUI
 using System;
 using AVFoundation;
 using Uno.Extensions;
@@ -52,3 +53,4 @@ internal void ApplyStretch()
 		}
 	}
 }
+#endif
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.MediaPlayer.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.MediaPlayer.cs
index 11e2a7ef24f5..30620a60ff30 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.MediaPlayer.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.MediaPlayer.cs
@@ -1,4 +1,4 @@
-#if __ANDROID__ || __IOS__ || NET461 || __MACOS__
+#if !HAS_UNO_WINUI && (__ANDROID__ || __IOS__ || NET461 || __MACOS__)
 
 using System;
 using System.Timers;
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.Properties.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.Properties.cs
index be3944f4cb4f..3555ee84b43f 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.Properties.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.Properties.cs
@@ -1,4 +1,4 @@
-#if __ANDROID__ || __IOS__ || __MACOS__
+#if !HAS_UNO_WINUI && (__ANDROID__ || __IOS__ || __MACOS__)
 
 using System;
 using Windows.Media.Playback;
@@ -7,7 +7,7 @@ namespace Windows.UI.Xaml.Controls
 {
 	public partial class MediaTransportControls
 	{
-		#region IsFullWindowButtonVisible Property
+#region IsFullWindowButtonVisible Property
 
 		public bool IsFullWindowButtonVisible
 		{
@@ -22,9 +22,9 @@ public bool IsFullWindowButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsPlaybackRateEnabled Property
+#region IsPlaybackRateEnabled Property
 
 		public bool IsPlaybackRateEnabled
 		{
@@ -39,9 +39,9 @@ public bool IsPlaybackRateEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsFastRewindEnabled Property
+#region IsFastRewindEnabled Property
 
 		public bool IsFastRewindEnabled
 		{
@@ -56,9 +56,9 @@ public bool IsFastRewindEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsFastRewindButtonVisible Property
+#region IsFastRewindButtonVisible Property
 
 		public bool IsFastRewindButtonVisible
 		{
@@ -73,9 +73,9 @@ public bool IsFastRewindButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsFullWindowEnabled Property
+#region IsFullWindowEnabled Property
 
 		public bool IsFullWindowEnabled
 		{
@@ -90,9 +90,9 @@ public bool IsFullWindowEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsFastForwardEnabled Property
+#region IsFastForwardEnabled Property
 
 		public bool IsFastForwardEnabled
 		{
@@ -107,9 +107,9 @@ public bool IsFastForwardEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsCompact Property
+#region IsCompact Property
 
 		public bool IsCompact
 		{
@@ -124,9 +124,9 @@ public bool IsCompact
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(false, OnIsCompactChanged));
 
-		#endregion
+#endregion
 
-		#region IsSeekEnabled Property
+#region IsSeekEnabled Property
 
 		public bool IsSeekEnabled
 		{
@@ -141,9 +141,9 @@ public bool IsSeekEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true, OnIsSeekEnabledChanged));
 
-		#endregion
+#endregion
 
-		#region IsStopEnabled Property
+#region IsStopEnabled Property
 
 		public bool IsStopEnabled
 		{
@@ -158,9 +158,9 @@ public bool IsStopEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsFastForwardButtonVisible Property
+#region IsFastForwardButtonVisible Property
 
 		public bool IsFastForwardButtonVisible
 		{
@@ -175,9 +175,9 @@ public bool IsFastForwardButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsStopButtonVisible Property
+#region IsStopButtonVisible Property
 
 		public bool IsStopButtonVisible
 		{
@@ -192,9 +192,9 @@ public bool IsStopButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsVolumeButtonVisible Property
+#region IsVolumeButtonVisible Property
 
 		public bool IsVolumeButtonVisible
 		{
@@ -209,9 +209,9 @@ public bool IsVolumeButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsSeekBarVisible Property
+#region IsSeekBarVisible Property
 
 		public bool IsSeekBarVisible
 		{
@@ -226,9 +226,9 @@ public bool IsSeekBarVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true, OnIsSeekBarVisibleChanged));
 
-		#endregion
+#endregion
 
-		#region IsPlaybackRateButtonVisible Property
+#region IsPlaybackRateButtonVisible Property
 
 		public bool IsPlaybackRateButtonVisible
 		{
@@ -243,9 +243,9 @@ public bool IsPlaybackRateButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsZoomEnabled Property
+#region IsZoomEnabled Property
 
 		public bool IsZoomEnabled
 		{
@@ -260,9 +260,9 @@ public bool IsZoomEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsZoomButtonVisible Property
+#region IsZoomButtonVisible Property
 
 		public bool IsZoomButtonVisible
 		{
@@ -277,9 +277,9 @@ public bool IsZoomButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsVolumeEnabled Property
+#region IsVolumeEnabled Property
 
 		public bool IsVolumeEnabled
 		{
@@ -294,9 +294,9 @@ public bool IsVolumeEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsSkipBackwardButtonVisible Property
+#region IsSkipBackwardButtonVisible Property
 
 		public bool IsSkipBackwardButtonVisible
 		{
@@ -311,9 +311,9 @@ public bool IsSkipBackwardButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsNextTrackButtonVisible Property
+#region IsNextTrackButtonVisible Property
 
 		public bool IsNextTrackButtonVisible
 		{
@@ -328,9 +328,9 @@ public bool IsNextTrackButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region FastPlayFallbackBehaviour Property
+#region FastPlayFallbackBehaviour Property
 
 		public Media.FastPlayFallbackBehaviour FastPlayFallbackBehaviour
 		{
@@ -345,9 +345,9 @@ public Media.FastPlayFallbackBehaviour FastPlayFallbackBehaviour
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(default(Media.FastPlayFallbackBehaviour)));
 
-		#endregion
+#endregion
 
-		#region IsSkipForwardEnabled Property
+#region IsSkipForwardEnabled Property
 
 		public bool IsSkipForwardEnabled
 		{
@@ -362,9 +362,9 @@ public bool IsSkipForwardEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsPreviousTrackButtonVisible Property
+#region IsPreviousTrackButtonVisible Property
 
 		public bool IsPreviousTrackButtonVisible
 		{
@@ -379,9 +379,9 @@ public bool IsPreviousTrackButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsSkipForwardButtonVisible Property
+#region IsSkipForwardButtonVisible Property
 
 		public bool IsSkipForwardButtonVisible
 		{
@@ -396,9 +396,9 @@ public bool IsSkipForwardButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsSkipBackwardEnabled Property
+#region IsSkipBackwardEnabled Property
 
 		public bool IsSkipBackwardEnabled
 		{
@@ -413,9 +413,9 @@ public bool IsSkipBackwardEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region ShowAndHideAutomatically Property
+#region ShowAndHideAutomatically Property
 
 		public bool ShowAndHideAutomatically
 		{
@@ -430,9 +430,9 @@ public bool ShowAndHideAutomatically
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true, OnShowAndHideAutomaticallyChanged));
 
-		#endregion
+#endregion
 
-		#region IsRepeatButtonVisible Property
+#region IsRepeatButtonVisible Property
 
 		public bool IsRepeatButtonVisible
 		{
@@ -447,9 +447,9 @@ public bool IsRepeatButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsRepeatEnabled Property
+#region IsRepeatEnabled Property
 
 		public bool IsRepeatEnabled
 		{
@@ -464,9 +464,9 @@ public bool IsRepeatEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsCompactOverlayEnabled Property
+#region IsCompactOverlayEnabled Property
 
 		public bool IsCompactOverlayEnabled
 		{
@@ -481,9 +481,9 @@ public bool IsCompactOverlayEnabled
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 
-		#region IsCompactOverlayButtonVisible Property
+#region IsCompactOverlayButtonVisible Property
 
 		public bool IsCompactOverlayButtonVisible
 		{
@@ -498,7 +498,7 @@ public bool IsCompactOverlayButtonVisible
 				typeof(MediaTransportControls),
 				new FrameworkPropertyMetadata(true));
 
-		#endregion
+#endregion
 	}
 }
 #endif
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.cs
index 18ef6ce12a8d..b1d9304dd017 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControls.cs
@@ -1,4 +1,4 @@
-#if __ANDROID__ || __IOS__ || NET461 || __MACOS__
+#if !HAS_UNO_WINUI && (__ANDROID__ || __IOS__ || NET461 || __MACOS__)
 using System;
 using System.Timers;
 using Uno.UI.Converters;
diff --git a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControlsHelper.cs b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControlsHelper.cs
index 153f8d618af9..657024d589da 100644
--- a/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControlsHelper.cs
+++ b/src/Uno.UI/UI/Xaml/Controls/MediaPlayer/MediaTransportControlsHelper.cs
@@ -1,4 +1,4 @@
-#if __ANDROID__ || __IOS__ || __MACOS__
+#if !HAS_UNO_WINUI && (__ANDROID__ || __IOS__ || __MACOS__)
 namespace Windows.UI.Xaml.Controls
 {
 	public partial class MediaTransportControlsHelper 
diff --git a/src/Uno.UWPSyncGenerator.Reference/Uno.UWPSyncGenerator.Reference.csproj b/src/Uno.UWPSyncGenerator.Reference/Uno.UWPSyncGenerator.Reference.csproj
index 8a3e0d7d41fa..096287c1dbb8 100644
--- a/src/Uno.UWPSyncGenerator.Reference/Uno.UWPSyncGenerator.Reference.csproj
+++ b/src/Uno.UWPSyncGenerator.Reference/Uno.UWPSyncGenerator.Reference.csproj
@@ -122,7 +122,7 @@
       <Version>6.2.9</Version>
     </PackageReference>
     <PackageReference Include="Microsoft.WinUI">
-      <Version>3.0.0-preview3.201113.0</Version>
+      <Version>3.0.0-preview4.210210.4</Version>
     </PackageReference>
     <SDKReference Include="WindowsDesktop, Version=10.0.19041.0">
       <Name>Windows Desktop Extensions for the UWP</Name>