The Mail app on your Mac is a decent email app and comes pre-installed and set as the default email client. However, if you don’t want to use the Mail app as the default email client, you can use a different email app, such as Microsoft Outlook or Mozilla Thunderbird, and I’ll show you how.
Third-party email clients on the Mac may ask you, when you first run them, whether you want to set that email app as the default email client. If you missed that opportunity, or the app never asked, you can set the default email client manually. The process of changing the default email client on your Mac is not obvious and may seem a bit strange, but it’s easy to do.
How to Change the Default Email Client on Your Mac
To begin, open the Mail app and select Preferences from the Mail menu. Yes, you heard me right. As strange as it seems, the default email client is set from within the Mail app.
On the Preferences dialog box, make sure the General screen is active. If not, click the General button on the toolbar at the top. Then, click on the “Default email reader” drop-down list. All email apps installed into the Applications folder are listed. Select an app from the list.
NOTE: If you downloaded an email app in a .zip file and you extracted the app to a folder other than the Applications folder, you can choose Select from the drop-down list to select that email app. However, you should put the email app into the Applications folder, just like any other Mac app. Then, the app will be available in the “Default email reader” drop-down list.
Close the Preferences dialog box by clicking the X button.
Now, when you send email from within other Mac apps or from links on web pages, your new default email client is used. I wish we could do this in iOS as well. Hopefully in iOS 11!