Want to take all your cherished emails with you to a new favored device? Find out here how to transfer mail to a new Mac and copy “On My Mac” email folders using Apple Mail.
First, No Sooner Had She Stepped Ashore Than Asking for a Cup of Tea
Alas, such a refreshment was not to be yet for Catherine, the Portuguese princess that had arrived in Portsmouth on 13 May 1662 to become wife of Charles II and queen of — Britain.
This, story has it, is how the British tradition of drinking tea got started. Together with a few other culinary customs, Catherine of Braganza brought tea to the British Isles.
Want to pack up, step ashore — and ask for your On My Mac email folders in Apple Mail?
How to Transfer “On My Mac” Mail Folders to a New Mac
Copy Individual “On My Mac” Email Folders
To move and copy an On My Mac email folder to a new computer from one Apple Mail for Mac installation to another:
1) On the old Mac:
- Open the folder you want to copy under On My Mac in Apple Mail on macOS.
“On My Mac” folders: Email folders in Apple Mail listed under On My Mac are kept locally on the computer; unlike messages in email accounts such as Gmail or iCloud Mail, these emails and folders do not automatically synchronize to new devices and have to be copied or moved by hand.
Moving sub-folders: Mail will export any sub-folders to that folder as well. You can choose whether you want to import them on the new Mac. - Select Mailbox | Export Mailbox… from the menu.
- Choose a location that will allow you to move the created file to the new Mac.
Where to save folders: An online drive such as iCloud Drive, OneDrive or Google Drive work well; you can also use an external hard drive, a phone or tablet or AirDrop, for example. - Click Choose.
Now transfer the created MBOX (*.mbox) files to the new Mac.
To avoid issues during copying, you can compress the files: click on the MBOX file with the right mouse button and select Compress “___.mbox” from the context menu.
2) On the new Mac:
- Open Mail.
- Select File | Import Mailboxes… from the menu.
- Make sure Apple Mail is selected under Import data from:.
- Click Continue.
- Highlight the MBOX file (or files; you can import more than one folder at a time).
- Now click Choose.
- Make sure all folders you do want to import are checked.
- Click Continue.
- Now click Done.
- Find the imported folders under the Import in the On My Mac section.
Transfer All “On My Mac” Mail Folders to a New Mac
Have a whole slew of folders under On My Mac in Apple Mail? You need not export them all individually to migrate your email to a new Mac.
Time needed: 15 minutes
To copy all local email folders from one computer’s On My Mac section in macOS Mail to another:
- In macOS Finder, press Command Shift G.
- Type
~/Library/Mail/V10.Different versions: For versions of Mail other than 16 (from macOS Ventura 13 and Sonoma 14), the folder where Mac Mail stores emails will be different, e.g., “V7” or “V8” (macOS Monterey) instead of “V10”.
Which version: How to Find Your Mac macOS Version (and Build Number) - Click Go.
- Go through the folders named with random strings until you find one that has MBOX files whose names correspond to the folders under On My Mac in Mail.
- Highlight and copy all MBOX files to the new computer.
One ZIP file: To turn all files into one document you can copy easily, highlight the MBOX files, click with the right mouse button on one of them and select Compress __ Items from the context menu that has appeared (or ZIP the files using the Mac command line, of course).
- See above for importing all On My Mac folders on a new computer.
“Like new”: How to Reset Mail on a Mac
(Tested with Mail under macOS Sequoia 15.3–15.6, Sonoma 14.3–14.6, Ventura 13.3, Monterey 12.0, and Catalina 10.15; first published January 2019, last updated September 2025)