How to Import MBOX Emails to Mozilla Thunderbird?

With the correct configuration, importing MBOX emails into Mozilla Thunderbird is a fairly simple procedure. First, use Thunderbird's Add-ons Manager to install the ImportExportTools NG add-on. Restart Thunderbird after installation, then right-click on the folder or mailbox where you wish to import your emails. Depending on your preferred folder structure, pick ImportExportTools NG > Import MBOX file. Your MBOX file will be imported straight into Thunderbird after you browse and choose it.

Verify that the MBOX file is correctly formatted and free of corruption. A third-party program like BLR MBOX Converter can simplify and improve the process if you're having trouble with manual import or wish to import several MBOX files at once.