How Do You Import a .mbox into Thunderbird to View the Emails?

Problem scenario
You want to view the emails in a .mbox file. You are using Thunderbird. What do you do?

Solution
Overview: Install the ImportExportTools NG add-on. Have another email account (an empty one or something else) that can accept the emails in Thunderbird configured.

Procedures

1. Open Thunderbird
2. Click the hamburger symbol (of three horizonal bars in the upper right hand corner)
3. Go to "Add-ons"
4. Search for "ImportExportTools"
5. Click the hamburger symbol (of three horizonal bars in the upper right hand corner)
6. A mailbox, even an empty one must be configured.
7. Warning: this will import your .mbox emails into the mailbox you have configured. Right click the "Local Folders" on the left-hand side in Thunderbird.
8. Go to "ImportExportTools NG" -> "Import mbox file"
9. It should have the default option checked of "Import directly one or more mbox files" and click "OK"
10. Browse to your .mbox file, highlight it, and press Enter.
11. It may take time for the messages to be viewable. You may want to close Thunderbird and re-open it.
12. Optional step: We recommend right-clicking the header row of "Subject"…"Correspondents"…"Date" and choose "From:". Many .mbox files have spam, trash, and inbox emails all in one folder.