How to Import Mail from Mozilla Thunderbird in Gmail

With Gmail offering so much space, so useful a search engine and so universal access, why use all this potential on new mail you receive at your Gmail address only? Wouldn't it be handy if the mail you already have in Mozilla Thunderbird were integrated, archived, accessible and searchable as well?
Sure, you can forward the messages, but elegant and fully functional this is not. The messages will lose their original senders, and mail you sent will not appear to be sent by you. Gmail will not be able to do its very useful "conversation" work, putting together emails that belong together.
Fortunately, Gmail offers IMAP access, which turns importing mail into a drag-and-drop affair.

Import Mail from Mozilla Thunderbird in Gmail Using IMAP

To copy your messages from Mozilla Thunderbird to Gmail:

• Set up Gmail as an IMAP account in Mozilla Thunderbird.
• Open the folder containing the emails you want to import.
• Highlight the messages you want to import.
  • Press Ctrl-A or Command-A to highlight all messages.
• Select Message | Copy from the menu, followed by the target Gmail folder:
  • for messages you have received: [Gmail]/All Mail
  • for sent mail: [Gmail]/Sent Mail
  • for emails you want to appear in the Gmail inbox: Inbox
  • for messages you want to show up in a label: the folder named like the Gmail label

Import Mail from Mozilla Thunderbird in Gmail Using Gmail Loader

A little tool (some would say "hack") called Google Gmail Loader also can take your Mozilla Thunderbird mail and move it to Gmail in a clean and seamless way.
To copy your messages from Mozilla Thunderbird to Gmail:

• ›› Step by Step Screenshot Walkthrough

• Make sure you have compacted all folders in Mozilla Thunderbird.
• Download and extract Gmail Loader.
• Double-click gmlw.exe to launch Gmail Loader.
• Click Find under Configure Your Email File.
• Locate the file pertaining to the Mozilla Thunderbird folder you want to import into Gmail.
  • You can find the files corresponding to your Mozilla Thunderbird folders under your Mozilla Thunderbird message store folder.
  • You probably have to make Windows display hidden files and folders to see the Application Data folder.
  • Use the files that do not have a file extension (not the .msf files).
• Click Open.
• Make sure mBox (Netscape, Mozilla, Thunderbird) is selected under File Type: in Gmail Loader.
• If you are migrating sent messages, choose Mail I Sent (Goes to Sent Mail) under Message Type:, otherwise select Mail I Received (Goes to Inbox).
• Type your full Gmail address under Enter your GMail Address.
• Click Send to GMail.

Sending Trouble?

If you run into problems moving mail to Gmail using Gmail Loader, try changing the SMTP server. Try using "gmail-smtp-in.l.google.com", "gsmtp183.google.com" or "gsmtp163.google.com" with authentication not enabled, or enter the SMTP server details given to you by your ISP.