Guide to Exporting Mail From Thunderbird

A command line approach to exporting mail

The Thunderbird email client


Whether the switch is voluntary or not, dreaded or eagerly anticipated, changing email programs is usually a challenge. To make sure it is not also a struggle accompanied by frustration and loss of data, you'll want to take your existing contacts, filters, and—most importantly—emails with you in a smooth manner.

If your past email program is Mozilla Thunderbird, your starting point is good. Thunderbird stores your messages in Mbox format, which can be opened in a text editor and is easily converted to other email programs. Here's how:

Export Mail From Thunderbird to Another Email Program

To export messages from Mozilla Thunderbird to a new email program:

  1. Download mbx2eml and extract it to your Desktop. This small application converts Mbox format files to EML format using the Command-Line.
  2. Click on the Desktop with the right mouse button.
  3. Select New | Folder from the menu.
  4. Type "Mail" in the field provided.
  5. Click Enter.
  6. Open your Mozilla Thunderbird Profile directory—where Thunderbird keeps your settings and messages—in Windows Explorer or File Explorer.
  7. Open the Local Folders folder.
  8. Highlight all files named like folders in your Mozilla Thunderbird store folder that have no extension.
  9. Exclude "msgFilterRules," "Inbox.msf," and any other .msf files.
  10. Copy or move the highlighted files to the new Mail folder on your Desktop.
  11. Open a Command Prompt window via Start > All Programs > Accessories > Command Prompt. In Windows 10, open the Start menu, input "cmd" in the empty field, and select Command Prompt from the results.
  12. Type "cd "in the command prompt window.
  13. Drag and drop the Mail folder from your Desktop onto the Command Prompt window.
  14. Press Enter in the Command Prompt window.
  15. Type "mkdir out" and press Enter.
  16. Type "..\mbx2eml * out" and press Enter.
  17. Open the Mail folder from your Desktop.
  18. Open the Out folder.
  19. From the subfolders of the Out folder, drag and drop the .eml files onto the desired folders inside your new email program.

If your Local Folders folder has any subfolders with mailboxes you want to keep, repeat the process for each of these folders.