There are a couple ways to do this given your current settings in Thunderbird, but they both will result in downloading '''all''' the messages on the server again. You will then have many duplicates e-mails. This is because you are accessing your e-mail through POP. With POP, all the e-mails from the server get sent to Thunderbird, Thunderbird saves those e-mails on your computer, then tells the server to delete those mails from the server. Unless you set an option in Thunderbird to '''not''' tell the server to delete the e-mails. You can set up another "account" in Thunderbird for your e-mail address which uses IMAP. With IMAP, Thunderbird continually communicates with the server to show the e-mails on the server, but doesn't necessarily save them on your computer. With that IMAP account, you can then copy just the e-mail you want from the server to the folder you want it in. Then consider which type of way you want to access your e-mail in the future: POP or IMAP. Which instructions would you like? '''1.''' Don't change your e-mail settings, but download all the messages on the server again, producing duplicate e-mails on your computer. '''2.''' Temporarily set up an IMAP account for your e-mail address to get that one e-mail, then delete that IMAP account. '''3.''' Permanently switch from a POP account to an IMAP account.