An MBOX file stores a whole mailbox folder as one long text file. EML stores one email per file. Splitting MBOX into EML is useful when you need to attach specific emails to a case, open them in a different program, or keep them as separate records.
Thunderbird can do it for free one folder at a time. For many MBOX files, or when you want sensible file names, a converter is quicker.
| MBOX | EML | |
|---|---|---|
| Emails per file | A whole folder | One |
| Opens in | Thunderbird, Apple Mail | Outlook, Thunderbird, Apple Mail, most mail apps |
| Good for | Moving a mailbox between apps | Sharing, evidence, archiving single messages |
| Standard | No single strict standard | Internet Message Format (RFC 5322) |
EML is also the easiest step on the way to other formats. Once you have EML files you can turn them into PDFs or bring them into Outlook.
.eml file per message.For a single email, open it and use File > Save As > File, which saves it as EML.
Limits: one folder at a time, and you have to import every MBOX into Thunderbird first.
Magic Soft MBOX Converter converts MBOX straight to EML without an email client, and handles many MBOX files in one run.
Choose Single file, Folder tree or Thunderbird under Source Mode, then browse to the files.
Check the folders and tick the emails or folders you need.
Click Export and select EML. Pick a file naming pattern, such as date and subject, so the files sort in order.
Choose a destination and click Start Export. The folder structure is recreated in the output.
A pattern like 2024-03-14 - Invoice 1182.eml sorts in time order in File Explorer, which helps when you hand the files to someone else.
Double-click an EML file and Windows opens it in your default mail program, usually Outlook or Thunderbird. On a Mac, Apple Mail opens it. If nothing opens it, see how to open EML files.
For one or two folders, Thunderbird and ImportExportTools NG do the job for free. For lots of MBOX files, readable file names and the folder tree kept intact, use the converter. Need a spreadsheet instead of files? See exporting MBOX to CSV.
Yes. Import the MBOX into Thunderbird and export the folder as EML with the free ImportExportTools NG add-on.
Yes. Attachments stay inside each EML file, the same way they were inside the MBOX.
MBOX Converter loads a whole folder of MBOX files with Folder tree mode and converts them in one run.
No. The original Date header stays in each EML file. File timestamps on disk will show the export date, so use a date-based naming pattern if order matters.
Yes. Classic Outlook opens EML files when you double-click them, one message at a time.
