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Packaging a Win32 app isolation application with Visual Studio

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This page will cover everything needed to package an application to leverage Win32 app isolation.

Important

This feature is in preview: Some information relates to a prerelease product which may be substantially modified before it's commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Prerequisites

The following are required to package an application into an isolated Win32 app:

  • Visual Studio version 17.10.2 or higher

Step 1 - Install the required workloads in Visual Studio including Windows 11 SDK 10.0.26100.0 (or greater)

Open the Visual Studio Installer and Modify the existing installation. On the Workloads tab check the Windows application development box (and optionally check the C++ WinUI app development tools box for development in C++). The Windows 11 SDK 10.0.26100.0 (or greater) is also required.

A screenshot showing the required workloads to be installed in Visual Studio

Step 2 - Create your app project

In Visual Studio, create a new C# or C++ project using the template Blank App, Packaged with Windows Application Packaging Project (WinUI 3 in Desktop). Click Create and then select 10.0.26100.0 (or later) for Target Platform Version (TPV) and Target Platform Minimum Version (TPMinV).

A screenshot showing a template for a Blank App with Windows Packaging project in Visual Studio

A screenshot showing the New Project screen in Visual Studio

A screenshot showing the new WinUI project screen in Visual Studio

Step 3 - Install Microsoft.Windows.SDK.BuildTools version 10.0.26100.1742 or later with NuGet

Go to Project -> Manage NuGet Packages to install Microsoft.Windows.SDK.BuildTools version 10.0.26100.1 (or later).

A screenshot showing the manage NuGet packages screen in Visual Studio

A screenshot showing the Microsoft.Windows.SDK.BuildTools package on the NuGet screen in Visual Studio

A screenshot showing the info for the Build Tools package on the NuGet screen in Visual Studio

Step 4 - Edit the Packaging.appxmanifest and project files

In the manifest file, the following changes will need to be made:

Note: Isolated win32 applications are not compatible with other application types within the same package.

  • Add xmlns:uap18="http://schemas.microsoft.com/appx/manifest/uap/windows10/18" to the <Package> element if it's not there already.

    • Add uap18 to IgnorableNamespaces at the end of the <Package> element.

  • In <Dependencies> change TargetDeviceFamily to <TargetDeviceFamily Name="Windows.Desktop" MinVersion="10.0.26100.0" MaxVersionTested="10.0.26226.0" />.

    Note

    Not all features are available in the minimum build, check out the release notes for more detailed information. In addition, the following manifest changes enable the app to become an isolated app, but it can continue to run as a Win32 app in operating systems where Win32 app isolation isn't supported.

  • In <Application> replace any existing entrypoint/trustlevel/runtimebehavior with EntryPoint="Windows.FullTrustApplication" uap18:EntryPoint="Isolated.App" uap18:TrustLevel="appContainer" uap18:RuntimeBehavior="appSilo".

  • In <Application> extensions, remove any EntryPoints=* or Executable=* as those are inherited from the parent <Application>

  • Add desktop7:Scope="user" to the extension element for windows.protocol.

    Note

    By default, Visual Studio will automatically add <rescap:Capability name="runFullTrust"> to <Capabilities> due to the app being a packaged Win32. This should be removed unless the app has other manifested extensions which can affect the user global state, such as comServer or FirewallRules, since those require the runFullTrust capability.

A screenshot showing the packaging app config in Visual Studio

  • Add <AppxOSMaxVersionTestedReplaceManifestVersion>false</AppxOSMaxVersionTestedReplaceManifestVersion> in the wapproj file, right after the target platform version lines A screenshot showing the project file config in Visual Studio

Step 5 - Build and Publish App Packages

Build the Visual Studio solution.

A screenshot showing the solution building in Visual Studio

Publish the App Package by using the Create App Packages... wizard.

A screenshot showing the create app packages wizard in Visual Studio

A screenshot showing the create step in the app packages wizard in Visual Studio

After publishing the App Packages, the Output location displayed shows the root directory where the MSIX package is published by version. Open on the version folder to find the Install.ps1 file for installing the app.

A screenshot showing the packaging was created successfully by the wizard in Visual Studio

App Isolation overview

Application Capability Profiler

Packaging an isolated Win32 app with MSIX