Go to Firefox Options/Preferences > Applications and look for the mailto option under Content Type. The dropdown menu next to it is where you can specify which email program you want to use. It could be Gmail, Yahoo! Mail, or any other desktop email program such as Thunderbird or Microsoft Outlook.
For linking to a desktop client, you’ll have to use the Use Other… option in the dropdown menu and navigate to your email program via Explorer (or via Finder, if you’re on a Mac).
The mailto dropdown menu has a couple of other useful options:
- Always Ask – To specify an email program a mailto: link on a case by case basis.
- Use Chrome – To have mailto: links from Firefox open in Chrome. Of course, you’ll just get a blank new tab in Chrome if you haven’t configured Chrome first to open mailto:links.
Can’t find your webmail service listed in the mailto dropdown menu? You need the MailtoWebmails add-on. It allows you to choose from various popular webmail services and configure any of them as the default handler for mailto: links in Firefox. If you can’t find the webmail you use in that list either, don’t worry. The add-on gives you the option to add it yourself.