Mozilla Thunderbird is a free, cross-platform and feature-rich email program. It is a good choice for those using different operating systems (Windows, Mac, Linux). Thunderbird supports the traditional POP protocol and the newer IMAP protocol to retrieve messages. The key difference between those two access protocols is where email is stored and where it is accessible.
When email is retrieved using POP, it is deleted from the mail server and will only be accessible on the computer where it was downloaded to. This mode is a good choice for users with slow Internet connections and those accessing their email offline. Conversely, with IMAP email messages remain stored on the mail server and can be accessed from another computer or using WebMail. Mail stored on the mail server counts against your web storage quota.
First, download and install Mozilla Thunderbird. Follow the steps at this URL to install Thunderbird.
When Thunderbird is started for the first time, it will automatically prompt you to add a new email account (see step 1 below). To add an account at a later time, choose Tools > Account Settings, then press the Account Actions button on the lower left and choose Add Mail Account. On Linux, the Account Settings option is under Edit Menu.
Step 1: Email Address and Password
Step 2: Mail Server Settings
Typically the wizard can determine the mail server settings automatically. If you do not get two green bullets next to the Incoming and Outgoing server entries, verify that the settings are as shown below.
Step 3: Advanced Mail Settings (optional)
Several additional configuration settings can be done to get the most out of Thunderbird. Popular configuration changes include:
Turning on message caching
In the main Thunderbird window, on the left, right click on the mailbox name (Inbox) and choose Properties in the pop-up menu. Select the Synchronization tab, and check the "Select this folder for offline use" check box.
Turning off global indexer (if you experience performance problems or simply do not need it)
Choose Tools > Options in the main menu, then select Advanced. Uncheck the "Enabled Global Search and Indexer" check box.
Specifying how message deletion should be handled
Choose Tools > Account Settings in the main menu, then on the left side select the Server Settings option under the appropriate mail account. Select "Just mark it as deleted" to cross out deleted message, or "Remove it immediately" to remove the message. Both options will put the deleted message in the Trash folder.