Importing emails crashes Apple Mail

Hi there,

First, thanks in advance for your help.

I’m due to lose access to my previous employer’s email (a university), so I’ve been advised to download what I would like to keep. It’s a Microsoft Exchange account, accessed through Apple Mail, and I have 18,000 emails in the account.

My first thought was to import these emails into Devonthink Pro. I installed the Apple Mail plugin (following the instructions carefully), then tried to export the emails from Apple Mail using the plugin / export function (Add to DEVONthink 3). If I select one or two emails to export, the plugin works well and imports the emails into Devonthink. But if I select anything larger (e.g., 100 emails), Mail hangs. After this happens, I have to force quit Apple Mail and reopen it. In Devonthink, the log shows one email with the error “connection went invalid while waiting for a reply” and the rest show the following error: “*** -[NSDistantObject methodSignatureForSelector:]: remote object does not recognize selector: ‘dataSource’”

Next I attempted to drag and drop these 18,000 emails from Apple Mail into a new folder in my Devonthink database. That initiates a transfer. Emails import, but very slowly. What happens is that approx. 1-5 emails will appear in Devonthink, and then after a few minutes Apple Mail will hang, and no further emails will import. I’ve tried leaving it for a few hours and nothing changes—Apple Mail just remains unresponsive, with the spinning wheel. I’ve tried restarting both applications and restarting the computer and that does not help. I’ve also tried reinstalling the Apple Mail plugin (though I’m not sure if this would affect the drag and drop functionality). What’s more, opening Devonthink at any point automatically prompts Apple Mail to open and then Apple Mail instantly hangs (each time maybe 5 emails are imported before it hangs). So I cannot have both applications open until I cancel the ‘Importing emails’ process from the Activity window in Devonthink.

Any help would be much appreciated!


That’s a lot of mail, and working the the vagaries of Microsoft Exchange and Apple Mail brings a lot of variables to the mix.


  • Do the import Exchange → Apple Mail → DEVONthink in batches, say 100-500 at a time (pick a quantity that works)
  • Or (my preference, I think) copy all the mail (at once or in batches … whatever works) to folder(s) Exchange → Apple Mail “On My Mac” to get them onto your machine or to another email account, say one that does IMAP which might work with Mail better than Exchange. Or just leave the mails “On My Mac”.
  • If getting the mails to your machine still is an issue, install and use Microsoft Outlook (which the University can probably provide if you don’t already have it) which might work better with Microsoft Exchange and use it to get the mails onto your machine for handling (moving into an IMAP or “on my mac” somehow or another)
  • Disable the Preferences > Mail > Conversation options in DEVONthink.
  • Make sure you’ve enabled Full disk access and all Automation requests for DEVONthink 3 in System Preferences > Security & Privacy > Privacy.
  • If you have submailboxes, import them instead of one massive mailbox.