Message Synchronizing
–Keep messages in all folders for this account on this computer checkbox: when using IMAP, only the headers are stored on your computer. When viewing a message, the application accesses the message content located on the server. If this option is enabled, the application will store a local copy of each message on your computer, allowing you to read messages offline.
–Advanced button: select the message folders you want to save.
Disk Space
–Synchronise all messages locally regardless of age option: save all messages on your local disk.
–Synchronise the most recent <N> Days/Weeks/Months/Years option: save messages for the selected period on the local disk.
–Don't download messages larger than <N> kB checkbox: disable saving messages larger than the selected size on the local disk.
–Don't delete any messages option: always store all messages on the local disk or server.
–Delete all but the most recent <N> messages option: store only the selected number of recent messages.
–Delete messages more than <N> days old: store only messages no older than the selected number of days.
–Always keep flagged messages checkbox: always keep messages marked with a star.