How to Set Thunderbird to Leave Mail on the Server

This very brief tutorial will guide you through the steps to set Thunderbird to leave mail on the server. Leaving your mail on the server can be helpful if you use Thunderbird on a portable USB drive to check your email while away from your main computer. That way when you return to your main desktop/laptop, you can still download all of your email.

Please note: even though this guide was published back in 2008, it has been updated in 2021 to be current with the latest version of Thunderbird.

It’s also important to note that you only need to apply these settings if you’re using a POP3 mail server. If you email provider supports it, you may want to look into using an IMAP server instead, as it has a number of benefits over POP3 – including the ability to sync your messages, so you don’t have to worry about leaving them on the server or not.

1. Launch Thunderbird and click the Menu button found in the Mail Toolbar (see screenshot below, it’s the button that looks like 3 lines on top of each other) and then select Account Settings
2. Select Server Settings from the column on the left side of the Account Settings window.
3. Make sure there is a check-mark in the box labelled Leave messages on server, remove the check-mark from the box labelled For at most, and it’s up to you to decide if you want to have the messages removed from the server if you delete them from Thunderbird.
4. Now when you check your email with Thunderbird, a copy will be left on the server.