You need to go into the browser that you would like to use, for example Chrome or Firefox, then select preferences, then select ‘ make this the default browser’. Setting the default browser is slightly different. You go into the calendar application and from there you can choose any default calendar application. So to set the default calendar application it’s the same. This is actually the way it works across all of OS X, although it is a little inconsistent. You set the OS X default email application from within the preferences of the mail app itself. To set the default application that automatically launches when you open a new email, you have to open the OS X built-in mail app, go to preferences, and then select the app you want to use. That’s because the default app for opening email is set from within the mail app itself. Even if you search for ‘Mail’ in the System Preferences nothing comes up. I went searching through the Apple ‘System Preferences’ and could not find a setting anywhere to set the default email client. To open all files of this type with this app, click Change All. Click the pop-up menu, then choose the app. Earlier versions of macOS relied on two folders/Library. In the Info window, click the arrow next to Open with. IDG Everything in the Login Items listwhether added by you or by an appopens automatically when you log in. You can also Control-click the file, then choose Get Info. Select the file, then choose File > Get Info. I wanted to send email with the old fashioned OS X Mail app. On your Mac, click the Finder icon in the Dock to open a Finder window. I’m not sure why – I must’ve changed a setting somewhere – but recently whenever I click ‘send an email’ in OS X it opens up a Chrome browser window and tries to send a new email through Gmail.