Format Atlas

Guides

Choose a format for saving or migrating email

Choose according to whether you need one message, a whole mailbox, or an Outlook item, and back up the source before importing.

Which format should you choose?

Choose by the role each file plays in your workflow.

  • Save one email → EML
  • Migrate many messages together → MBOX
  • Save an Outlook item individually → MSG
  • Before import → back up the source mailbox

Decide the unit to save

EML stores individual messages, MBOX can hold many messages in a mailbox, and MSG represents an Outlook item. Verify that the destination email app can import the chosen format.

Check attachments and personal data

Messages can include attachments, addresses, and sensitive body text. Do not open suspicious attachments; confirm recipients and storage locations before sharing.

Formats to consider

EML

Good for: Saving or transferring an individual email

Less suitable for: Packaging a large mailbox into one file

MBOX

Good for: Migrating or preserving a mailbox

Less suitable for: Quickly sharing just one message

MSG

Good for: Saving individual Outlook items

Less suitable for: Sending to environments without checking Outlook compatibility

Before you export

  • Back up the original mailbox before importing.
  • Email and attachments may contain personal or confidential information.

Related comparisons

MSG vs EMLMSG stores Outlook items and can represent more than email, including appointments and contacts. EML is commonly used to save or transfer one internet email message at a time.EML vs MBOXEML commonly stores one email message. MBOX groups multiple messages in a mailbox file. Choose by the unit you need to preserve or move.MBOX vs MSGMBOX typically stores multiple email messages in a mailbox file, while MSG is commonly used for an individual Outlook item. Choose according to the unit being migrated and the destination application's import support.

Guides

Choose a calendar or contact file formatUse ICS to import events into a calendar, VCF for contact apps, and CSV when you need to edit a list as a table.Verifying messages after an email migrationAfter choosing a format, record scope and metadata, then compare bodies, attachments and counts in a trial import before migrating the working mailbox.

References and specifications