Migrating from Thunderbird to Apple Mail
Step 1: Configure Apple Mail
By default, Apple Mail is already installed on all Macs...you'll find it in the Applications folder on your computer. University IT has instructions for the initial setup of Apple Mail here: https://tech.rochester.edu/tutorials/access-office-365-on-mac-using-apple-mail/
Please note: The initial process of setting up Apple Mail with Office365 will give you an option to use your Mail, Contacts, Calendar, Notes, and Reminders applications with Office365. If you already use the non-Mail apps on your Mac, synchronizing them with O365 could have unforeseen side-effects. I would suggest unchecking all but "Mail" for now, and only activate the others (via the Internet Accounts preference pane) when you're absolutely sure you want to sync them.
Step 2: Migrating old e-mail to Apple Mail
There are two ways to perform the migration...a "manual" process that exports/imports your e-mail using a Thunderbird add-on utility or an "automatic" process that relies on Apple Mail to do all the work.
- === Option 1: the "automatic" process ===
1. On your Mac, navigate to the /Applications/Utilities folder and run the "Terminal" application. When it opens you should see a text window with a command prompt. Type in this command exactly as it appears below:
chflags nohidden ~/Library/
If the command runs successfully the command prompt should simply reappear. Now type in this command to exit the Terminal application:
exit
2. Now we need to import your mailboxes into Apple Mail. Run Apple Mail, then at the top click on "File -> Import Mailboxes". An Import window will appear giving you several options ...select "Thunderbird". Click the "Continue" button.
3. A file selector will now appear...navigate to the following directory...
/<your home folder>/Library/Thunderbird/Profiles/
...then click the "Choose" button. The Import window should now show all of the mailboxes it plans to import. Uncheck any folders that start with the word "ImapMail", then click "Continue" to begin the importing process (which will take a while).
- === Option 2: the "manual" process ===
Use this process if the "automatic" option fails to work properly.
First step is to install an add-on in Thunderbird called ImportExportTools. We will use it to export your mail folders from Thunderbird in a format Apple Mail can easily import. Please note: this process can only export Thunderbird mail folders residing at the "main" folder level. If you have nested mail folders (ie: mail folders within other mail folders), this process will NOT import those nested folders. You'll need to move all of these nested folder to the "main" folder level by dragging them to the "Local Folders" header.
1. Go to this website to download the ImportExportTools add-on for Thunderbird: https://addons.thunderbird.net/en-US/thunderbird/addon/importexporttools/ This add-on should download to your "Downloads" folder.
2. Open Thunderbird, then at the top click on "Tools -> Add-ons". In the resulting window click on "Extensions" in the column on the left. In the area to the right, click on the gear icon and select "Install Add-on From File". When the file selector appears, select your "Downloads" folder select the file "importexporttools-3.3.0-sm+tb.xpi", then click the "Open" button. A dialog box should appear asking you to verify you want to install the add-on. Do so. You'll then need to restart Thunderbird for the change to take place.
3. On your desktop, create a folder called "Exported Mailboxes".
4. When Thunderbird restarts you'll now be in a position to export your mail from Thunderbird. Within Thunderbird, right/control click the "Local Folders" header in the column on the left, then from the resulting menu "ImportExportTools -> Export All The Folders". A file selector will open...navigate to your desktop, then select the "Exported Mailboxes" folder you created in the last step and click on the "Open" button. The add-on will now proceed to export all of your local mail folders.
5. Now we need to import your mailboxes into Apple Mail. Run Apple Mail, then at the top click on "File -> Import Mailboxes". An Import window will appear giving you several options ...select "Files in mbox format". Click the "Continue" button. A file selector will now appear...navigate to your "Desktop" folder, select the "Exported Mailboxes" folder, then click the "Continue" button. The Import window should now show all of the mailboxes it plans to import...uncheck any you might not want to import, then click "Continue" to begin the importing process (which will take a while).
Please Note: The Apple Mail import window does show an option for Thunderbird but it doesn't work. Please don't try to use it.
6. Once the importing process is complete, you should see your mailbox folders appear in Apple Mail under the "On My Mac" header in the column on the left.
Step 3: Migrating addresses/contacts
We can migrate your address book(s) from Thunderbird to Apple Mail (which utilizes the "Contacts" application on your Mac for this).
1. Within Thunderbird, at the top click on "Window -> Address book".
2. In the resulting window you'll see a few address books listed in the column on the left. Highlight the "All Address Books" header, then at the top click on "Tools -> Export". An Export window for each address book should now appear. Select where the file should be saved (your Desktop is fine), set the format to "vCard", then click the "Save" button to save the file. Do this for each address book.
3. Run the "Contacts" application on your Mac...it's located in the Application folder.
4. Within the Contacts application at the top click on "File -> Import". In the resulting file selector navigate to the folder where you saved the exported address books, select one of them, then click the "Open" button. You should see a dialog box asking if you're sure you want to import X number of addresses. Click the "Import" button to confirm. Repeat this step for each address book you want to import.
5. Once you're done importing address books, return to Apple Mail and create a new e-mail message. You should find that your old address book entries now appear in Apple Mail when you enter a "To:" address.