Default Mail App

A lightweight macOS utility to inspect and change your system default mail app (mailto: handler).

What It Does

• Lists installed apps that can handle mailto: links.
• Shows the current default mail app.
• Lets you switch the default mail app from the app UI.
• Falls back to clear manual guidance when macOS blocks automatic switching.
• Includes compatibility paths for newer and older macOS UI/API behavior.

Why This Exists

On some systems, changing the default mail reader in system UI can be confusing or hidden. This app gives you a single place to see what is available and switch quickly.

Requirements

• macOS 11.0+
• Xcode 16+

Build and Run

1. Open Default Mail App.xcodeproj in Xcode.
2. Select the Default Mail App scheme.
3. Build and run.

Open Source + Binary Releases

This repo is intended for:

• Source distribution (project files included)
• Precompiled signed binaries (published in GitHub Releases)

Suggested release process:

1. Archive from Xcode.
2. Export a signed .app.
3. Zip the app bundle.
4. Attach the zip to a GitHub Release.

Notes

• The app is unsandboxed by design because changing URL handler defaults is restricted under app sandboxing.
• On some configurations, macOS may still require manual changes in Mail settings.
• If app icon updates look stale in Finder/Dock, relaunch and refresh icon cache (killall Dock).

Tests

Unit tests are included using Apple’s Testing framework and cover:

• Bundle identifier deduplication behavior
• Installed-app filtering and sorting behavior
• Display-name fallback priority behavior