BOX File

What are BOX files and how to open them

Are you having problems opening a BOX file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your BOX files.

What is a BOX file?

BOX files have multiple uses, and Email Message is one of them. Read more about the other uses further down the page.

Email Message

Files that contain the .box file extension are most commonly used to store email messages. A variety of email applications use the .box file extension to store collections of email messages. These email messages can be opened individually by opening the contents of the BOX file.

The .mbox and .dbx file extensions have been replacing the BOX file format over time. Popular email programs that use the .box file extension include the Lotus Notes Mailbox, FoxMail, and Calypso email applications.

How to open BOX files

Important: Different programs may use files with the BOX file extension for different purposes, so unless you are sure which format your BOX file is, you may need to try a few different programs.

While we have not verified the apps ourselves yet, our users have suggested ten different BOX openers which you will find listed below.

Last updated: August 24, 2026

All known file formats using extension .BOX

While Email Message is a popular type of BOX-file, we know of 3 different uses of the .BOX file extension. Different software may use files with the same extension for different types of data.

Boom Box Project

Boom Box Project files define song setups created with Boom Box, an interactive beat-making and sample-triggering program for the Commodore Amiga by Dr.T's Music Software. The format stores groove arrangements using internal IFF samples, patterns, effects settings, mix-levels, tempo, and optional digital effects and echo. It was part of Boom Box's workflow allowing playback of included or user-created rap beats, drums, guitar riffs and other sound-effects via keyboard or remix screen.

These files are saved by Boom Box when users build or remix arrangements. During use, the program loads the sample data (often in IFF form), associated pattern-sequence and settings like effects or echo, then plays back or allows live triggering of those parts. The file format encapsulates all necessary data so that arrangements can be re-loaded, edited in the remix screen, and mixed-down or played live without having to reassign individual samples or effects each time.

Files in this format begin with the ASCII signature BOX1 at offset 0. They also typically contain strings such as BOOMBOX_FILES, DRUMS, .IFF, SND0, SQD0, which help identify internal structure including sample sections and sequence data.

Microsoft Store Download Package

We know that one BOX format is Microsoft Store Download Package. We have not yet analyzed in detail what these files contain and what they are used for. We're working on it.

Various apps that use files with this extension

These apps are known to open certain types of BOX files. Remember, different programs may use BOX files for different purposes, so you may need to try out a few of them to be able to open your specific file.

Help us help others

File.org helps thousands of users every day, and we would love to hear from you if you have additional information about BOX file formats, example files, or compatible programs. Please use the links below or email us at submit@file.org to discuss further.