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What is the MBOX format, and what is it used for?
A file in MBOX (short for "mailbox") format is used to store email databases. All messages from one mail folder are stored in one text file. When you change your email client, the .mbox file is used to both export and import data.
There are four main variants of the MBOX format: mboxo, mboxrd, mboxcl, and mboxcl2. Some email clients use modifications of these formats.
What programs use MBOX files?
Email systems use the MBOX message database format for Windows, macOS, Linux and Unix, and popular email applications:
- Mozilla Thunderbird,
- Mac/Apple Mail,
- IncrediMail,
- Spicebird,
- SeaMonkey,
- Sylpheed,
- Opera Mail,
- Entourage,
- Eudora,
- PocoMail and others.
.Mbox files are used by some email services and servers to store and transfer message databases. For example, Gmail utilizes MBOX format to export messages via Google Takeout.
MS Outlook does not support MBOX format, but messages from .mbox files can be opened in Outlook after conversion.
You can copy messages from Outlook to MBOX using utilities to export messages to MBOX, convert messages from PST to MBOX or from MSG to MBOX.
What is the MBOX file data?
MBOX stores the contents of the entire message folder in one file. The messages are presented as a chain of emails in chronological order. New messages are being appended to the end of the .mbox file. Each message begins with the word "From" followed by a space, the sender's email address, and a space-separated timestamp.
Next follows the message itself in EML format. The last line of each message is empty.
The message contains:
- Message headers are lines of named values. Each header starts with a name and a colon. A colon is followed by a space and a header value, which can span one or several lines or be empty.
- The message body usually contains text and attachments. The message text can be in HTML, RTF, or any other format. Attachments can be documents, pictures and other files saved in an .mbox file in one of the supported encodings.
Where is the MBOX file located?
Depending on the operating system (Windows / macOS) and email client, the location of .mbox files may vary.
Here are the default folders with .mbox files for the major email clients:
- Thunderbird / Eudora 8.0: %AppData%\Thunderbird\Profiles\ProfileName
- MBOX on Mac: /User/Library/Mail/mailboxes
- Entourage 2008: /Users/ProfileName/Documents/Microsoft User Data/Office 2008 Identities/Main Identity
- Eudora: %AppData%\Qualcomm\Eudora Folder
- PocoMail: %AppData%\PocoMail\Mail
- Opera Mail: %LocalAppData%\Opera Mail\Opera Mail\mail\store\accountX
- SpiceBird: %AppData%\Spicebird\Profiles\ProfileName
- SeaMonkey: %AppData%\Mozilla\SeaMonkey\Profiles\ProfileName
- Sylpheed: %AppData%\Sylpheed\Mailboxes\Mail
How to view the MBOX file without installing email apps?
The MBOX message database can be viewed by using any text editor. However, this is not the best way: a large number of messages are unreadable data in various encodings.
To ensure convenient viewing, it is recommended to convert MBOX to EML.
Splitting large .mbox files into separate EML message files has several advantages. Specifically, you can:
- quickly view the messages you need without an .mbox file,
- forward selected messages to other users,
- import .eml files to Outlook and other email clients,
- convert individual messages from EML to HTML or from EML to PDF.
Another way to view and print email messages from .mbox files while preserving formatted text, message data, attachments is to convert MBOX to PDF.
How to open an MBOX file in Outlook?
To open MBOX in Outlook, you need to import .mbox files to Outlook or to convert MBOX to PST or MSG format supported by Outlook:
- Using the utility for importing emails from MBOX to Outlook, you can quickly copy your MBOX email database to Microsoft Outlook, retaining the original folder structure and Internet headers.
- By converting MBOX to MSG, you are not only able to open emails in Outlook but also work with them in Windows Explorer, search, share, or simply store them in native Outlook format.
- Converting email from MBOX to PST is almost the same as importing MBOX to Outlook with some minor differences:
- When converting MBOX to PST, you can create new .pst files. When importing into Outlook, messages are copied to existing mailboxes, PST data files, or Exchange Server Public Folders.
- When converting a message database from MBOX to PST, you can use macros in the target path, enabling you to create .pst file sets depending on your needs. For example, you can group your email by year or by the recipient.
- During the conversion process, the resulting .pst files can be split by size.
How to back up the MBOX file?
Common causes of .mbox file corruption are:
- Errors on hard drives and other data storage devices;
- Network failures;
- Improper system shutdown;
- System hardware failures;
- Malfunction of the email service;
- Virus or trojan attacks.
Repairing damaged .mbox files is a complex task. The highest risk danger of errors in the .mbox file is that you may not know about partial damages to your email until the moment you need it, and it may be too late to take any actions.
To prevent information loss, it is recommended to make backup copies of your .mbox files. You can do so by using our utilities for saving messages from MBOX into other formats like MSG, EML, PST, and PDF format.
To backup an .mbox file, convert MBOX to PST format or save data from MBOX to separate files in one of three ways:
- Save all messages from .mbox file separately in MSG format for Outlook;
- Convert the .mbox file into separate messages in EML format;
- Convert messages from MBOX to PDF documents to read them on most devices using Adobe Reader or web-browsers.
You can individually save attachments from one or more MBOX files.
FAQ
How to open an MBOX file on Mac?
You can open a .mbox file on Mac in one of these ways:
Method 1.
- Convert MBOX to PDF for viewing messages in Adobe Reader.
Method 2.
- Convert messages from MBOX to EML or from MBOX to PST.
- Convert the resulting EMLs to HTML or PST to HTML for viewing files in a web browser.
How to import MBOX file on Mac?
To import MBOX to Mac, simply use Apple Mail:
- Open the app.
- Go to the File Menu > Import Mailboxes.
- Check the Files in the MBOX format option and select the .mbox file(s).
- Click the OK button and the imported files will go into a new Import folder under On My Mac in Mail.
How to open an MBOX file in Gmail?
One method to open or import an .mbox file in Gmail is to use Microsoft Outlook:
- Connect your Gmail mailbox to your Outlook profile.
- Import one or more MBOX files into Outlook.
- The contents of the .mbox file will appear in your Gmail account after synchronization is completed.
How to open an MBOX file in Chrome?
To open individual messages from an .mbox file in Google Chrome, you need to convert them:
- Split MBOX file into separate messages in EML format.
- Convert the required EML files to HTML.
- Open the resulting HTML files in your Google Chrome or any other browser.
How to convert MBOX to PST?
- Open the utility for converting messages from MBOX to PST.
- Select the .mbox file or folder containing files in MBOX format.
- Specify the destination folder for .pst files.
- Run the utility.
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