Clicking an email address link (a mailto: link) on a website or in an electronic document in macOS automatically launches Apple Mail by default. However, if your daily communication workflow relies on Microsoft Outlook, Mozilla Thunderbird, Spark, or web-based services like Gmail, having Apple Mail pop open can be disruptive. Unlike other operating system settings configured in System Settings, macOS historically anchors default mail client assignments inside Apple Mail’s preferences pane.
Configuring Your Default Email Client in Apple Mail Settings
Even if you never actively use Apple Mail to send messages, its configuration dialogue contains the primary system registration handler for all incoming mailto: URL requests.
- Open the Mail app on your Mac (located in your Applications folder or via Spotlight). (If Mail prompts you to set up an account, you can dismiss or bypass the prompt if an alternative client is already installed.)
- Click Mail in the top menu bar and select Settings… (or press Command + ,).
- Ensure the General tab is selected at the top of the settings window.
- Locate the very first option labelled Default email reader:.
- Click the drop-down menu currently displaying Mail.app.
- Choose your preferred alternative email application from the list of installed software (such as Microsoft Outlook, Spark Desktop, or Thunderbird).
- If your application is installed in a non-standard directory, select Select…, browse to the executable, and click Open.
- Close the Settings window.
From this point forward, clicking any mailto: hyperlink across Safari, Chrome, Slack, or PDF documents will automatically launch your designated third-party email application.
Setting a Web-Based Email Service as Default
If you do not use desktop email clients and prefer opening links directly inside webmail (such as Google Workspace or Outlook on the web):
- Chrome Protocol Handler: Open Google Chrome, navigate to
mail.google.com, and look at the right side of the address bar for the double-diamond Service handler icon. Click it and select Allow to let Chrome handle email links. - Browser Extensions: Lightweight browser extensions (such as Mailto: for Gmail) intercept system
mailto:clicks and route them directly to a fresh browser tab with a pre-addressed draft window.
Verifying System Default Handlers in macOS System Settings
In modern macOS versions, you can also verify default application associations by opening System Settings > Desktop & Dock or checking default browser integration to ensure smooth URL protocol handoffs.