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Recommendations/Script Creation Request for Migrating 30GB of POP mail to G Suite


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Anyone have suggestions on migrating 30GB of POP mail living in Apple Mail to G Suite? What I really want is something that can accomplish the equivalent of an r-sync or FreeFileSync, but for mboxes in Mail. A client has hundreds of folders and the drag and drop method hangs forever, drops out, and doesn't work consistently. Does someone know anyone who can write a script to accomplish this? I can throw a little money at it but not a ton. I'm totally stunned there are no tools in existence to accomplish this. What about a script for Homebrew or Cakebrew? Are there communities of starving coders seeking stardom somewhere who want to tackle this project? GitHub? Fiverr? Any advice would be appreicated!


Thanks. 🙂

3 Answers

I recall having this sort of discussion before, maybe back in the Facebook group.....  Yes, back in March 2018 you asked a very similar question!!

And therefore I still have the same idea, of setting up a mail server on the Mac, performing a local move of POP to IMAP (which should be faster & reliable), then creating a public domain/address/certificate for that server so that G-Suite can pull the IMAP data across at its own rate and with its own error recovery methods/reporting. 

Thanks @kiwigraham! I've never set up a mail server but this all sounds like a lovely idea. If I have the mbox files on an external HD, should I install MacOS server on my Mac as a first step to create that mail server? And in terms of creating a public domain/address/certificate for that server, could you point me to a good knowledge base article or resource on how to do that?

Cheers. 🙂


Sorry, I was being a little bit glib in my late evening post - and the ability to use macOS Server Mail service for this task is now dependent on having a version prior to 5.7.1. ( tells about the deprecation of features & possible alternatives - which I haven't tried myself). Pointing the mail repository at an external drive should be feasible.

I don't have an article to point to for making the mail server publicly accessible via SSL connection but the steps I've previously done are:

  • Set up a dynamic DNS subdomain for the connection if there isn't a domain already applied to your IP address (As far as I recall this doesn't have to be the "real" domain.)
  • Ensure port forwarding of ports 143 & 993 for incoming IMAP connections
  • Generate and install an SSL certificate for the server (G-Suite migration will only talk to SSL authenticated servers) - I've used a 30 day trial certificate like this:
  • Steps for installing the cert on the server may need to be gleaned from the doco of whatever mail server software is being used.

All of this might be too much work for just your "30GB client" but if you think it might be something you need to do again in the future, or want to offer as one of your "services", the bulk of the work wouldn't need to be repeated if the mail server was configured on one of your Macs.

@kiwigraham -- I wonder if I could also set up the mail server on my Synology to do this?? Isn't that what Synologys are for?? 🙂


Just chiming in here. 

Great question, and the reality is there is no easy way to do this. That said, the drag-and-drop(-and-hope!) method has proven successful for me every time I’ve done it. And I’ve found that logging into the web interface of the destination mail server is often the best way to know if things are moving. 
As you know, Mail does a lot of “prep work” here, so things won’t appear on the destination right away, but eventually they will, and that can be a relieving thing to see. 

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FYI I've posted a job onto Upwork to have this app built: