Maildir and MBOX

Maildir and MBOX are just the file formats to store email messages to a local system. Earlier, MBOX was used as a format to store emails on a cPanel server; but currently, Maildir is mostly preferred. In MBOX format, messages are stored in the same file on the server. Whereas Maildir stores messages in a tree form with unique names on individual files.

To know the difference between Maildir and Mbox formats, read about them from below:

What is the Maildir Format for Storing Messages?

Maildir format was specifically made to remove the inadequacies of MBOX files. As messages in the Maildir directory are; saved in a new subdirectory in a tree form. Maildir can be accessed by multiple users at a time. There is a specific naming convention while storing messages in Maildir. In Maildir, any locking system is not required.

The subdirectories formed by Maildir are described as below:

New: All the new incoming emails are stored in this subdirectory. To indicate a new mail to the user the date and time are written on it. For storing messages, a Maildir uses RFC 822 format to display Return-path and Delivered-to line.

Cur: This directory is the same as the New directory, but it stores only the mails that a user has read.

Tmp: Tmp stands for Temporary in a Maildir file extension. It ensures proper delivery of emails and stores all temporary emails.

What is MBOX Format for Storing Messages?

MBOX is the traditional method to store emails on cPanel servers. Each message is saved in a single file and stored in the form of a series. To separate each message a marker is applied where the one message ends and the other begins. A single MBOX file can be accessed in the read/write mode. While multiple working, a locking mechanism is required to maintain data consistency.

Difference Between Maildir and MBOX

Let’s clear out differences by knowing the advantages of using each file storage format:

Advantages of Maildir:

  • Maildir is faster and stable than MBOX.
  • It allows the marking of subdirectories easily.
  • The filtration process is easy as it keeps new messages, read messages, and temporary messages separate.
  • These files can be; transmitted over the network with any compatibility issue.
  • For users of Maildir, both the courier and the dovecot servers are compatible.
  • It is the safest format with fewer instances of result manipulation.
  • In the Maildir directory, a single file is; generated for each incoming mail.

Advantages of MBOX:

  • The MBOX format of storing files is universally supported.
  • It includes new mail in the mailbox much faster.
  • Searching for a specific part of the text is; easier.
  • When used with the network file systems, it shows a locking problem.

These were the differences between Maildir and MBOX.

Key-Differences: Maildir v/s MBOX

  • Maildir format is much preferred than MBOX.
  • Maildir is more structured than MBOX.
  • MBOX is faster to transfer than Maildir.
  • Searching within the mail is easier in MBOX.


Here, I have mentioned the differences between Maildir and MBOX. I hope that you got an accurate knowledge of using a specific general format. Both formats have their concrete existence, and transferring a file is efficient with the MBOX format. But, viewing emails is much facilitated with the Maildir structured format.

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