Best way to do huge archive email task?

I’m trying to archive all my Apple Mail out into a new DTPO database so I can delete some of it out of the mail app.

I’m running on Sierra 10.12.6 and one of my Mailboxes has over 30K messages in it. I’ve already added the longer timeout via Terminal but I still can’t even get the smaller mailboxes (1-12K messages) to actually finish importing. I left one running for 4 hours but it never finished.

So, given the limitations of trying to archive huge mailboxes, what is the best way to try to capture everything and get it into the new DT database? Once in I can do archive on a regular basis to keep it up to date but I’m stumped trying to get the initial set in successfully.

A possibility is to split the mailbox into multiple smaller ones or import from individual mailboxes instead of a larger group of them.

I am trying to import some of the smaller mailboxes, one that has 104 total messages. Import proceeds successfully then it gets stuck with this message showing,

“Grouped 89 of 89 main conversation threads” with less than a minute remaining.

Been stuck like that for half an hour now.

Any ideas on how to get it moving?

Also any suggestions on exactly HOW to split huge mailboxes into smaller ones? I use one huge Reference Mailbox for all messages I want to save that are not part of specific lists. It currently has over 29,000 messages in it. I’m baffled as to how to make it small enough to actually import and then combine it again later.


There is an issue with importing and archiving e-mail using Sierra and the most recent version of DTPO. I contacted support and they had me downgrade to 2.9.17. That solved the hang problem for the smaller inboxes.

I am going to be experimenting with setting date restrictions to try to get the huge 30k+ message mailbox to import in pieces.

Note: We do suggest upgrading to High Sierra.

I’m doing some Android development and need to stay frozen on Sierra for now.