((better)) | Windows App Cert Kit

Version: 1.0 Target Audience: Windows App Developers, Testers, DevOps Engineers Applies to: Windows 10/11, UWP, WinUI 3, WPF, Windows Forms, and Desktop Bridge (MSIX) applications. 1. Executive Summary The Windows App Certification Kit (WACK) is a critical, mandatory testing tool provided by Microsoft. Its primary purpose is to validate that an application meets Windows platform technical requirements and security standards before submission to the Microsoft Store. However, even for apps not destined for the Store, WACK is an invaluable tool for identifying performance issues, memory leaks, and security vulnerabilities early in the development lifecycle.

| | Meaning | Store Action | | :--- | :--- | :--- | | Pass | Meets requirement. | Acceptable. | | Fail | Critical requirement violated. | Rejection. Must fix. | | Warning | Non-critical issue or best practice. | Review; may cause rejection if severe. | | Not Applicable | Test skipped (e.g., background task test for app with no background tasks). | Ignore. | 5. Common Failures & Fixes (Troubleshooting Matrix) | Failure Message | Likely Cause | Fix | | :--- | :--- | :--- | | "App cannot use more than 250 MB of private memory" | Memory leak or oversized cache on launch. | Use Memory Profiler in Visual Studio; implement IDisposable correctly. | | "Binary contains vulnerable cryptography" | Use of System.Security.Cryptography.SHA1CryptoServiceProvider | Replace with SHA256CryptoServiceProvider or higher. | | "Unsupported API in UWP app" | P/Invoke to kernel32!CreateFile | Use Windows.Storage.StorageFile API instead. | | "App start time exceeds threshold" | Synchronous initialization on UI thread. | Move startup logic to background thread; use splash screen to mask load. | | "Missing supported users element" | Package manifest missing uap:SupportedUsers | Add <SupportedUsers>singleUser</SupportedUsers> (or multipleUsers ) to manifest. | | "DLL hijacking risk" | LoadLibrary uses relative path without safe search. | Use absolute path or SetDllDirectory("") and LoadLibraryEx with LOAD_LIBRARY_SEARCH_* flags. | 6. Advanced: Automating WACK in Azure DevOps Create a pipeline step using the Windows App Certification Kit task (available in the Marketplace) or a PowerShell script. windows app cert kit

certrun.exe -Test AppCertKit -Task UWPAppCertification ^ -AppxPackagePath "C:\Build\MyUWP.appx" ^ -LaunchWinRTApp -AppxPackageUser "MyUser" The report categorizes results as: Version: 1