How can I back up a complete IMAP account?

Question

I have a huge IMAP email account that contains a lot of subfolders and a lot of messages (dating back to 2005). Is there a simple way to back up these folders and messages so I can delete them from the server?

I would like to retain the ability to browse and manage these archived messages, reply, or add addresses from these messages to my contacts - all preferably within Apple Mail.

If Apple Mail can't do it, what other options do I have?

Answer 1

In the lefthand sidebox you can just drag mailboxes from the imap location to the On My Mac location.

Otherwise See Mail's help for Archiving mailboxes

Archive the mailbox which puts it on your computer then import the mailbox

I am not certain if the directories are kept,

Answer 2

You can do it with offlineimap. I'm using it for my GMail and Fastmail accounts.

Install Homebrew (you must also install Xcode). With Homebrew, install offlineimap.

Create .offlineimaprc config file:

[general]
ui = ttyui
accounts = fastmail
maxsyncaccounts = 4
socktimeout = 60

[Account fastmail]
localrepository = fastmail-local
remoterepository = fastmail-remote

[Repository fastmail-local]
type = Maildir
localfolders = ~/Mail/Fastmail

[Repository fastmail-remote]
type = IMAP
remotehost = mail.messagingengine.com
remoteuser = username
remotepass = password

expunge = no
folderfilter = lambda foldername: foldername not in ['INBOX.Trash']

A big advantage of offlineimap is that it creates the folders you have on your IMAP server.

I'm reading my backup with mutt.

Answer 3

Just to Second, you can drag a folder from your inbox to On My Mac, however expect this process to take a long time if you have a large Mailbox, folder or sub folder, try with one small folder first and have a look at how it progresses the copy, you can do this by clicking on Window>Activity in Mail.

Answer 4

If you can or are willing to make the backup under Windows, IMAPSize enjoyed a very favorable reputation, back when I lived on Windows and frequented a couple of email fora.

Answer 5

You could create a Google mail account, add it to your mail client and drag the folders across. Then you could use gmail to browse all your mail.