C-Command Software Forum

Best practice for importing large email archives (>50GB)


I’ve been looking for such a solution for quite some time: a way to archive emails (2004-present) out of Apple Mail. I have basically two types of archives: 1) hand-made folders created by manually archiving emails from various senders into their respective mailbox folder; 2) but I also have archives of accounts (old email accounts) containing drafts, sent emails, inbox, etc.

My goal is simple: I want to archive those (including attachement) in a library of folders outside of Apple Mail and I want the whole archive to be searchable. Additionnaly, if at all possible, I’d like to fix duplication issues that may occured accross mailboxes (I may have archive the same email account more than once, creating duplicates in the process).

I read of two ways of importing mailboxes (containing multiple email messages):

  1. “ The recommended way to import from Apple Mail is to select some messages or mailboxes and press the capture key (F1 or fn-F1).” (in 3.5.1)


  1. “ It is better to drag and drop to the Dock icon or into EagleFiler’s window, or to use the capture key from the Finder.” (under “Importing Mailbox Hierarchies”) In Catalina the mail folder would be V7 if I’m not mistaken.

Basically should I work the import from within Apple Mail or should I process it directly from the Finder?

Many thanks and Happy Holidays,


EagleFiler can definitely help with that.

Currently, EagleFiler only removes duplicates within the same mailbox, but cross-mailbox duplicate detection may be possible in a future version.


The manual recommends using the capture key for ease. You can select what you want directly in Mail and don’t have to dig through folders in Finder and figure out which numbered files correspond to which mailboxes. But in your case, it sounds like you want to import whole hierarchies and you know how to find the relevant folders, so it will be faster and easier to just drag and drop them directly.

Fantastic: all very clear so I feel I can move forward and experiment! Thanks for the lightning fast reply: really appreciated!