Over on the X4U mailing list, cricket (an Apple mail.app engineer) wrote in with a process by which you can extract attachments from mail.app messages for storage in other locations. Here's what he wrote:
- Navigate to ~/Library/Mail/Mailboxes in the Finder (or to the location where you have stored some mailboxes that you want to extract attachments from).
- Find the mailbox you want to extract attachments from.
- Control-click on the mailbox and choose 'Show Package Contents'.
- Find the file called 'mbox' and option-drag it to another location (like the Desktop). Make sure to make a copy! Leave the original where it is.
- Drag the 'mbox' file on Stuffit Expander.
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