If you use POP3 to download your email, messages can remain on the mail server after they have been downloaded. This depends on how your email client is configured.
If your email client is set to leave a copy of messages on the server, the same messages may be downloaded again the next time your email client checks for new mail. This can also cause your mailbox to continue using storage space until messages are removed from the server.
While this is not usually something to be concerned about, you may eventually run out of mailbox storage if messages are left on the server indefinitely.
We recommend using IMAP rather than POP3 wherever possible. IMAP is supported by all major email clients and keeps your email synchronised with the mail server, making it easier to access your messages from multiple devices.
If you do need to use POP3, check your email client's settings to see whether it is configured to leave a copy of downloaded messages on the server.
If your mailbox is restored from a backup, messages that had previously been downloaded using POP3 may be restored to the mailbox as well. Your email client may therefore download these messages again, resulting in duplicate copies.
This is not normally a cause for concern. However, if you notice unexpected duplicate messages after a server restore, you can raise a Support Ticket with our Customer Services team so that we can check that the mailbox and backup have been restored correctly
Article ID: 257
Created On: Fri, Mar 13, 2015 at 11:50 AM
Last Updated On: Fri, Sep 18, 2026 at 1:38 PM
Online URL: https://www.heartinternet.uk/support/article/why-is-my-mail-client-downloading-duplicates-of-existing-emails.html