4 file types use the .dms file extension.

What is a DMS file?

A DMS file is a compressed Amiga disk image created using Amiga's Disk Masher System (DMS). It contains data intended for use with an Amiga computer. DMS files were originally used to transfer data among Amiga users via physical floppy disks, but are now most often used to share Amiga games, programs, and other files online, for use with Amiga emulators such as Amiga Forever.

More Information

How to open a DMS file

Category: Disk Image Files

Domino MIDI Sequence

A DMS file may also be a MIDI sequence created by Takabo Soft Domino, a free MIDI music editor. It contains binary data that defines the sequence's tracks, notes, timing, key signature, and metadata . DMS files are similar to .SMF and .MIDI files, except they can be opened only with Domino.

Domino allows amateur composers to create digital music by placing notes upon a piano roll. Each song a composer creates in Domino can consist of up to 16 tracks, allowing composers to create complex, multi-track songs. Composers can also adjust their songs' time and key signature, and they can add lyrics, comments, and cue points.

By default, Domino saves the songs that composers create as DMS files. From within Domino, composers can send the songs their DMS files contain to a MIDI device, or they can export the songs in the Standard MIDI ( .SMF ) format, for use with other MIDI programs and devices.

NOTE: Domino is a Japanese program, but a community-translated English version is available on GitHub.

You can open a DMS file with Domino (Windows). To do so, select File → Open... from Domino's menu bar. Then, navigate to and open your DMS file.

You can use Domino to export the sequence a DMS file contains as an .SMF (Standard Midi) file:

Programs that open DMS files

Updated: August 1, 2023

Dream Maker Script

A DMS file may also be a script file (i.e. "connect.dms") run by Dream Seeker, a client for playing online games. It was created by Dream Maker, part of the BYOND (Build Your Own Net Dream) suite of programs.

Programs that open or reference DMS files

Updated: 2006

Renamed Downloaded File

A DMS file may also be a file that has been downloaded and renamed by the Apple Safari web browser or the Apple Mail email client . It contains the contents of a file that did not have a file extension or was erroneously renamed when downloaded. The .dms extension is a result of a bug in Safari and Mail.

You most likely will encounter this type of DMS file only if you download a file that does not have a file extension in macOS with Safari or Mail. In some cases, Safari or Mail may also replace a valid extension with .dms or may append the .dms extension onto a file extension. For example, sample.pdf may become sample.dms or sample.pdf.dms when downloaded with Safari or Mail.

The bug is specific to Macs and has been reported across multiple versions of Mac operating systems, with some issues dating back to the early 2000s. While Safari and Mail are the typical perpetrators, the .dms renaming may also occur with other web browsers and programs.

To open a DMS file, rename the .dms extension with the appropriate extension for the file type. For example, if you know you downloaded an .XLSX file that was renamed with the .dms extension, click on the extension to highlight it and change it back to .xlsx . Then, you can open the file with a program that supports XLSX files.

Programs that open DMS files

Updated: July 2, 2020