For instructions on how to change your operating system's default e-mail program, see the next section of this article. Use (default) will automatically launch your operating system's email program (for example, Thunderbird, Outlook, Windows Live Mail Windows Mail Mail Evolution, KMail) to its message composition window.Always ask will prompt you each time you use a mail function for which program or service to use.Click on the Action column in the mailto row to change the action.Search for the Content Type mailto and select it.

In the General panel, go to the Applications section. Click the menu button and select Settings. Click the menu button and select Options Preferences.

In the Menu bar at the top of the screen, click Firefox and select Preferences.