Prepare to package a desktop application

This article lists the things you need to know before you package your desktop app. You might not have to do much to get your application ready for the packaging process, but if any of the items below applies to your application, you need to address it before packaging. Remember that the Microsoft Store handles licensing and automatic updating for you, so you can remove any features that relate to those tasks from your codebase.

Important

The ability to create a Windows app package for your desktop application (otherwise known as the Desktop Bridge) was introduced in Windows 10, version 1607, and it can only be used in projects that target Windows 10 Anniversary Update (10.0; Build 14393) or a later release in Visual Studio.

  • Your application requires a version of .NET earlier than 4.6.2. You need to make sure your application runs on .NET 4.6.2. You cannot require or redistribute versions earlier than 4.6.2. This is the version of .NET that shipped in the Windows 10 Anniversary Update. Verifying your application works on this version will ensure that your application will continue to be compatible with future updates of Windows 10. If your application targets the .NET Framework 4.0 or later, it is expected to run on .NET 4.6.2 but you should still test it.

  • Your application always runs with elevated security privileges. Your application needs to work while running as the interactive user. Users who install your application from the Microsoft Store may not be system administrators, so requiring your application to run elevated means that it won't run correctly for standard users. Apps that require elevation for any part of their functionality won't be accepted in the Microsoft Store.

  • Your application requires a kernel-mode driver or a Windows service. The bridge is suitable for an app, but it does not support a kernel-mode driver or a Windows service that needs to run under a system account. Instead of a Windows service, use a background task.

  • Your app's modules are loaded in-process to processes that are not in your Windows app package. This isn't permitted, which means that in-process extensions, like shell extensions, aren't supported. But if you have two apps in the same package, you can do inter-process communication between them.

  • Your application uses a custom Application User Model ID (AUMID). If your process calls SetCurrentProcessExplicitAppUserModelID to set its own AUMID, then it may only use the AUMID generated for it by the application model environment/Windows app package. You can't define custom AUMIDs.

  • Your application modifies the HKEY_LOCAL_MACHINE (HKLM) registry hive. Any attempt by your application to create an HKLM key, or to open one for modification, will result in an access-denied failure. Remember that your application has its own private virtualized view of the registry, so the notion of a user- and machine-wide registry hive (which is what HKLM is) does not apply. You will need to find another way of achieving what you were using HKLM for, like writing to HKEY_CURRENT_USER (HKCU) instead.

  • Your application uses a ddeexec registry subkey as a means of launching another app. Instead, use one of the DelegateExecute verb handlers as configured by the various Activatable* extensions in your app package manifest.

  • Your application writes to the AppData folder or to the registry with the intention of sharing data with another app. After conversion, AppData is redirected to the local app data store, which is a private store for each UWP app.

    All entries that your application writes to the HKEY_LOCAL_MACHINE registry hive are redirected to an isolated binary file and any entries that your application writes to the HKEY_CURRENT_USER registry hive are placed into a private per-user, per-app location. For more details about file and registry redirection, see Behind the scenes of the Desktop Bridge.

    Use a different means of inter-process data sharing. For more info, see Store and retrieve settings and other app data.

  • Your application writes to the install directory for your app. For example, your application writes to a log file that you put in the same directory as your exe. This isn't supported, so you'll need to find another location, like the local app data store.

  • Your application installation requires user interaction. Your application installer must be able to run silently, and it must install all of its prerequisites that aren't on by default on a clean OS image.

  • Your application uses the Current Working Directory. At runtime, your packaged desktop application won't get the same Working Directory that you previously specified in your desktop .LNK shortcut. You need to change your CWD at runtime if having the correct directory is important for your application to function correctly.

  • Your application requires UIAccess. If your application specifies UIAccess=true in the requestedExecutionLevel element of the UAC manifest, conversion to UWP isn't supported currently. For more info, see UI Automation Security Overview.

  • Your application exposes COM objects. Processes and extensions from within the package can register and use COM & OLE servers, both in-process and out-of-process (OOP). The Creators Update adds Packaged COM support which provides the ability to register OOP COM & OLE servers that are now visible outside the package. See COM Server and OLE Document support for Desktop Bridge.

    Packaged COM support works with existing COM APIs, but will not work for application extensions that rely upon directly reading the registry, as the location for Packaged COM is in a private location.

  • Your application exposes GAC assemblies for use by other processes. In the current release, your application cannot expose GAC assemblies for use by processes originating from executables external to your Windows app package. Processes from within the package can register and use GAC assemblies as normal, but they will not be visible externally. This means interop scenarios like OLE will not function if invoked by external processes.

  • Your application is linking C runtime libraries (CRT) in an unsupported manner. The Microsoft C/C++ runtime library provides routines for programming for the Microsoft Windows operating system. These routines automate many common programming tasks that are not provided by the C and C++ languages. If your application utilizes C/C++ runtime library, you need to ensure it is linked in a supported manner.

    Visual Studio 2017 supports both static and dynamic linking, to let your code use common DLL files, or static linking, to link the library directly into your code, to the current version of the CRT. If possible, we recommend your application use dynamic linking with VS 2017.

    Support in previous versions of Visual Studio varies. See the following table for details:

    Visual Studio versionDynamic linkingStatic linking
    2005 (VC 8)Not supportedSupported
    2008 (VC 9)Not supportedSupported
    2010 (VC 10)SupportedSupported
    2012 (VC 11)SupportedNot supported
    2013 (VC 12)SupportedNot supported
    2015 and 2017 (VC 14)SupportedSupported

    Note: In all cases, you must link to the latest publicly available CRT.

  • Your application installs and loads assemblies from the Windows side-by-side folder. For example, your application uses C runtime libraries VC8 or VC9 and is dynamically linking them from Windows side-by-side folder, meaning your code is using the common DLL files from a shared folder. This is not supported. You will need to statically link them by linking to the redistributable library files directly into your code.

  • Your application uses a dependency in the System32/SysWOW64 folder. To get these DLLs to work, you must include them in the virtual file system portion of your Windows app package. This ensures that the application behaves as if the DLLs were installed in the System32/SysWOW64 folder. In the root of the package, create a folder called VFS. Inside that folder create a SystemX64 and SystemX86 folder. Then, place the 32-bit version of your DLL in the SystemX86 folder, and place the 64-bit version in the SystemX64 folder.

  • Your app uses a VCLibs framework package. The VCLibs libraries can be directly installed from the Microsoft Store if they are defined as a dependency in the Windows app package. For example, if your application uses Dev11 VCLibs packages, make the following change to your application package manifest: Under the <Dependencies> node, add:
    <PackageDependency Name="Microsoft.VCLibs.110.00.UWPDesktop" MinVersion="11.0.24217.0" Publisher="CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US" />
    During installation from the Microsoft Store, the appropriate version (x86 or x64) of the VCLibs framework will get installed prior to the installation of the app.
    The dependencies will not get installed if the application is installed by sideloading. To install the dependencies manually on your machine, you must download and install the appropriate VCLibs framework package for Desktop Bridge. For more information about these scenarios, see Using Visual C++ Runtime in a Centennial project.

    Framework Packages:

  • Your application contains a custom jump list. There are several issues and caveats to be aware of when using jump lists.

    • Your app's architecture does not match the OS. Jump lists currently do not function correctly if the application and OS architectures do not match (e.g., an x86 application running on x64 Windows). At this time, there is no workaround other than to recompile your application to the matching architecture.

    • Your application creates jump list entries and calls ICustomDestinationList::SetAppID or SetCurrentProcessExplicitAppUserModelID. Do not programmatically set your AppID in code. Doing so will cause your jump list entries to not appear. If your application needs a custom Id, specify it using the manifest file. Refer to Package a desktop application manually for instructions. The AppID for your application is specified in the YOUR_PRAID_HERE section.

    • Your application adds a jump list shell link that references an executable in your package. You cannot directly launch executables in your package from a jump list (with the exception of the absolute path of an app’s own .exe). Instead, register an app execution alias (which allows your packaged desktop application to start via a keyword as though it were on the PATH) and set the link target path to the alias instead. For details on how to use the appExecutionAlias extension, see Integrate your desktop application with Windows 10. Note that if you require assets of the link in jump list to match the original .exe, you will need to set assets such as the icon using SetIconLocation and the display name with PKEY_Title like you would for other custom entries.

    • Your application adds a jump list entries that references assets in the app's package by absolute paths. The installation path of an application may change when its packages are updated, changing the location of assets (such as icons, documents, executable, and so on). If jump list entries reference such assets by absolute paths, then the application should refresh its jump list periodically (such as on application launch) to ensure paths resolve correctly. Alternatively, use the UWP Windows.UI.StartScreen.JumpList APIs instead, which allow you to reference string and image assets using the package-relative ms-resource URI scheme (which is also language, DPI, and high contrast aware).

  • Your application starts a utility to perform tasks. Avoid starting command utilities such as PowerShell and Cmd.exe. In fact, if users install your application onto a system that runs the Windows 10 S, then your application won’t be able to start them at all. This could block your application from submission to the Microsoft Store because all apps submitted to the Microsoft Store must be compatible with Windows 10 S.

Starting a utility can often provide a convenient way to obtain information from the operating system, access the registry, or access system capabilities. However, you can use UWP APIs to accomplish these sorts of tasks instead. Those APIs are more performant because they don’t need a separate executable to run, but more importantly, they keep the application from reaching outside of the package. The app’s design stays consistent with the isolation, trust, and security that comes with an application that you've packaged, and your application will behave as expected on systems running Windows 10 S.

  • Your application hosts add-ins, plug-ins, or extensions. In many cases, COM-style extensions will likely continue to work as long as the extension has not been packaged, and it installs as full trust. That's because those installers can use their full-trust capabilities to modify the registry and place extension files wherever your host application expects to find them.

    However, if those extensions are packaged, and then installed as a Windows app package, they won't work because each package (the host application and the extension) will be isolated from one another. To read more about how applications are isolated from the system, see Behind the scenes of the Desktop Bridge.

All applications and extensions that users install to a system running Windows 10 S must be installed as Windows App packages. So if you intend to package your extensions, or you plan to encourage your contributors to package them, consider how you might facilitate communication between the host application package and any extension packages. One way that you might be able to do this is by using an app service.

  • Your application generates code. Your application can generate code that it consumes in memory, but avoid writing generated code to disk because the Windows App Certification process can't validate that code prior to app submission. Also, apps that write code to disk won’t run properly on systems running Windows 10 S. This could block your application from submission to the Microsoft Store because all apps submitted to the Microsoft Store must be compatible with Windows 10 S.

Important

After you've created your Windows app package, please test your application to ensure that it works correctly on systems that run Windows 10 S. All apps submitted to the Microsoft Store must be compatible with Windows 10 S. Apps that aren't compatible won't be accepted in the store. See Test your Windows app for Windows 10 S.

Next steps

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Create a Windows app package for your desktop app

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