Compare
MBOX vs MSG
MBOX 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.
Which format should you choose?
Consider MBOX for mailbox-level archiving or transfer where the recipient supports it; use MSG when individual Outlook items and their supported properties must be handled separately.
Good fit for MBOX
Archive or migrate collections of emails
- Exporting a mailbox as one file
Good fit for MSG
Save or share individual Outlook items
- Emails, appointments, contacts, or tasks in Outlook workflows
Basic information
| Field | MBOX | MSG |
|---|---|---|
| Extension | .mbox, .mbx | .msg |
| MIME type | application/mbox | application/vnd.ms-outlook |
| Common uses | Archive or migrate collections of emails | Save or share individual Outlook items |
| How to open | Import with an MBOX-compatible mail client or migration tool. Back up the source mailbox first. | Use Outlook or a compatible viewer. Verify the file's origin before opening attachments. |
| Export or convert | After migrating or extracting EML files, compare message counts, dates, attachments, character display, and folder structure. | When converting to EML or another format, check message body, attachments, dates, and any appointment or contact fields. |
Choose by use case
Exporting a mailbox as one file
Archive or migrate collections of emails
MBOXEmails, appointments, contacts, or tasks in Outlook workflows
Save or share individual Outlook items
MSGKey point 1
MBOX groups multiple messages in a mailbox-oriented file.
More on the differencesKey point 2
MSG commonly represents an individual Outlook item.
More on the differencesMore on the differences
Check the destination client's import requirements and test representative messages, attachments, dates, and metadata. Preserve an untouched source copy and verify privacy and retention requirements before migration.
- MBOX is used by various mail clients for mailbox storage or exchange.
- MSG is associated with Outlook item storage and workflows.
- Conversion can change folder structure, properties, or message fidelity.
Frequently asked questions
Can every email app open both formats?
No. Support and import behavior vary by application and version.