Import a MBOX File into Gmail with Thunderbird

Restoring the emails from an export back into Gmail requires the use of 3rd party applications to import an MBox file. We recommend you use the Thunderbird application to transfer the MBox files from your Google account to UMD email.

You will be required to export your mail to the Mbox format. For instructions on how to create the MBox file, see Use Google Takeout to Export Data from Google Mail to an MBox File.

IMPORTANT: University personnel are prohibited from transferring, forwarding or sending UMD business email to or from a TERPmail or personal email account. For more information, read IT Standard Institutional Email (IT-14) and UMD Email Frequently Asked Questions (FAQ) in the IT Library.

Setup an Email account using Thunderbird

Download, install and configure the Thunderbird mail application. This article works with the version, 91.10.0 (64-bit).

Install "ImportExportTools" Add-On for Thunderbird

  1. Select Tools and click Add-ons and Themes from Thunderbird's menu bar.

    If your menu bar is missing, follow these instructions to restore it.

  2. Enter ImportExport in the box, Find more add-ons, press Enter (Windows) or Return (Mac) on the keyboard.

  3. From the search results, click +Add to Thunderbird.
    Click Add to Thunderbird
  4. Click Add to add ImportExportTools NG.
    Click add to add the Import Export Tool
  5. Click Restart now to restart Thunderbird after the add-on is installed.
    Click Restart now to restart Thunderbird

In Thunderbird Import the emails from the MBOX file for the label that you want to restore

  1. Click once on Local Folders.
    Illustration for clicking once on Local Folders in Thunderbird
  2. From the menu bar, select Tools>ImportExportTools NG>Import mbox file.
    Select Import mbox file
  3. Choose the import way, click OK.
    Choose the import way and click OK
  4. Select the MBox file.
    Select the Mbox File
  5. The MBox will appear under Thunderbird's local folders.

  6. If you wish to import the mbox into your UMD gmail account, click and drag the folder to your @umd Inbox.
    Mbox will appear under Local Folders         Drag the folder to the Inbox
    Once this is completed then you can log in to your Gmail account online and you should see all of the emails restored.
    The imported label will appear in Gmail.

Restore Missing Menu Bar

  1. Windows
    Picture of what how Thunderbird would appear without a Menu bar
    Right click at the top to click Menu Bar and Mail Toolbar.
    Demonstrating how to get the Menu Bar and Mail Toolbar back for Thunderbird
  2. Mac 

    This is due to expanding the Window for Thunderbird to Full Screen.  Move your cursor all the way to the top of the screen.
    A picture demonstrating moving your cursor all the way to the top of the screen.
    Click the green circle to resize the window.

    Picture demonstrating how to shrink the window

Return to Instructions

For further information, contact the Service Desk by email at or call 301.405.1500.