How to restore a Gmail backup using Thunderbird

This article will show you how to restore a Gmail backup file of type .MBox using Thunderbird Mail Client.

1. Go to https://www.mozilla.org/en-US/thunderbird/download to download the latest Thunderbird mail client if you don’t already have it.

2. Open thunderbird and select skip this and use my existing email to import to your new Gmail account.

3. Enter your Gmail Account Information under the Mail Account Setup windows and click Continue when done.
 
4. Make sure IMAP is selected and verify that your information is correct then click Done.
5. To import the .MBOX Gmail backup file you will need to install the “ImportExportTools” add-on for Thunderbird. You can get the add-on by going to the following  link https://addons.mozilla.org/en-us/thunderbird/addon/importexporttools/. Make note on the location where the add-on is downloaded.

6. In Thunderbird navigate to the Thunderbird Menu located in the upper right had corner and select Add-Ons.
7. In the Add-ons Manager window click on the gear next to the search box and select install add-ons from file. Locate the ImportExportTools file you downloaded and select install.

NOTE: You will get a warning message about installing add-on from unknown publishers, confirm the installation by selecting install.

8. After the installation restart Thunderbird.
 
9. In thunderbird go to the navigation pane located on the left hand side and right click on Local Folders. Navigate to ImportExportTools and select import mbox file.
10. Choose the option to import directly one or more mbox file and select OK. Navigate to the folder where you Gmail Backup file (.MBOX) exists and click Open.
NOTE: All emails from the backup will now start to import. This process might take a while to load all the emails. This stores the emails to your local folder, to import them to your google account proceed to the next step.
 
11. In Thunderbird navigate to the Local Folders and select the directory that you want to import to Gmail. Select all the emails contain in that folder and right click on the selection. Go to Copy To then select the Gmail account you want to imported to, and finally select the location you want to import it in with in Gmail.

Congratulations; the emails will now be imported to your Gmail account.