Feb 17, · Don't configure Thunderbird to save a copy of any messages you send in tools -> account settings -> copies & folders. Gmail's SMTP server automatically saves a copy of any message you send in the Sent Items folder for you. Set up IMAP and change your SMTP settings to read Gmail messages in other mail clients, like Microsoft Outlook and Apple Mail. When you use IMAP, you can read your Gmail messages on multiple devices, and messages are synced in real time. How to Use Mozilla Thunderbird 3 for Email. Mozilla Thunderbird is an email application for PC, Mac and Linux. It has a lot of customization options available and a variety of extensions you can add to improve functionality and appearance. For those who don’t like to use Outlook or other generic mail systems, this may be a good alternative.