Instructions for moving Thunderbird email files between computers

March 22, 2010


Note: Instructions were written for Thunderbird version 3 on computers running Mac OS 10.5 and and Windows XP.


Basic info and file locations:


1. Application folder


- Windows:  C:\Program Files\Mozilla Thunderbird

- Mac:  Macintosh HD/Applications/


2. Thunderbird data folder


- Windows:  C:\Documents and Settings\USERNAME\Application Data\Thunderbird

- Mac:  Macintosh HD/Users/USERNAME/Library/Thunderbird/


The Thunderbird data folder has two essential elements: 


a. The Profiles folder, which contains the personal profile, and

b. profiles.ini, which points Thunderbird to the correct profile folder.


3. The personal profile, which lives in the Thunderbird profiles folder




Here, nnnnnnnn.default is your personal folder (“nnnnnnnn” is a random 8-character filename).  This folder contains all personal email data (including all emails, address book, attachments, etc.)


Copying email files:


1. BACKUP ENTIRE nnnnnnnn.default DIRECTORY on your source machine, preferably to a DVD.  This is always a good idea if you value your email files!


2. Delete all files in the TARGET computer's Thunderbird data folder, except profiles.ini.  Note that you will need to edit this file if you are copying Thunderbird email files to the target computer for the first time.   (To edit the profiles.ini file, just open it in any text editor, and replace nnnnnnnn.default with the name of the profile as it appears on your source machine).


 3. Copy nnnnnnnn.default folder from the source computer to the appropriate folder in the target computer.


4. Delete the following files from the nnnnnnnn.default folder of the target computer:


- mailViews.dat

- virtualFolders.dat

- panacea.dat

- session.json


Note that I have to do this to get consolidated (multiple-account) mailboxes to display properly (see step 6 below).  This may not be necessary if you don’t have multiple mail accounts.


5. Start Thunderbird.  You should be able to download (receive) and send email immediately, because all your connection settings, etc., are stored in the profile that you copied onto the target computer.


6. Fixing consolidated mailboxes.  I have multiple email accounts, and the smart folders listed in left-hand-side pane do not show the consolidated “Inbox”, “Sent”, or “Trash”.  To fix this, I have done the following (not guaranteed to work, though!).  Click on individual-account inboxes, sent boxes, etc. one by one.  Thunderbird should show the number of unread messages in bold for each account.  Now, try clicking on the consolidated folder, e.g., “Inbox.”  If it still doesn’t show all messages, try quitting and restarting Thunderbird.  I have had to quit and restart Thunderbird several times to get it to properly display the consolidated mailboxes.


More information and resources:


Thunderbird profiles:


Thunderbird file names and file locations:


profiles.ini file:


MozBackup:  A Windows-only application designed to backup and restore Thunderbird (and other Mozilla) profiles.