Diagnose Windows app packaging, signing, install, identity, and SDK errors: untrusted or mismatched certificates, Add-AppxPackage and 0x80073CFx install failures, no package identity, C++/WinRT headers not generated. Use when an MSIX won't install or build, or an error code appears.
Install
npx skills add microsoft/winappCli --skill winapp-troubleshootnpx skills add microsoft/winappCli --skill winapp-troubleshoot -a claude-code -gnpx skills add microsoft/winappCli --skill winapp-troubleshoot -a codex -ggemini skills install https://github.com/microsoft/winappCli.git --path plugins/winapp/skills/winapp-troubleshootgh skill install microsoft/winappCli winapp-troubleshootgit clone --depth 1 https://github.com/microsoft/winappCli /tmp/microsoft__winappCli
mkdir -p ~/.claude/skills ~/.agents/skills
cp -R /tmp/microsoft__winappCli/plugins/winapp/skills/winapp-troubleshoot ~/.claude/skills/winapp-troubleshoot # Claude Code
cp -R /tmp/microsoft__winappCli/plugins/winapp/skills/winapp-troubleshoot ~/.agents/skills/winapp-troubleshoot # Codex, Cursor, Gemini CLI, Copilot, OpenCode