How to Replace the Default Email app on a Mac You can easily download Spark for Free and start using it, but if you're coming across mailto: links that still open the default Mail.app on a Mac, here's how to change the default email app on a Mac in six simple steps. While it's easy to move email accounts from Mail.app to a third-party email app like Spark, Apple hasn't really made it obvious to replace the default email app on a Mac. Mail.app is a decent app that handles most basic emailing duties, but falls considerably short when compared to the tons of features offered by other third-party clients like Spark Mail app. Have you been frustrated by clicking on email links on websites or in apps that open the default Mail.app on Mac instead of your own favorite email app? The Mail.app that comes pre-installed on a Mac cannot be removed, but can easily be replaced. How to replace the default email app on a Mac