.DSM file extension

To open .DSM files on Windows, install and open DeSmuME.

To open a .DSM file, use the DeSmuME Nintendo DS emulator and load/play the movie recording from within DeSmuME. Do not rename the extension—.DSM is not a standard video file, it is an emulator movie/input capture format.

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Last updated: June 11, 2026 · Reviewed by Julian Stricker

What “reviewed” means on this page

Format fit: whether the “what is this file?” description matches common real-world use of the extension, including category, typical MIME types, and aliases.
Opening paths: whether Windows / macOS / Linux steps read plausibly for current OS dialogs and default apps; we remove fantasy menus and unsafe shortcuts.
Security framing: whether risk notes match the extension class (for example executables vs plain data) and whether affiliate wording does not contradict the security section.
Sources and further reading: whether external links point to vendors, standards bodies, or other primary references where possible; we avoid inventing details we cannot ground.
Limits: this is clarity and safety-messaging QA, not a guarantee that every statement is exhaustive or that every binary you download is harmless.

Full methodology in the Imprint — The Imprint also states where AI is used and what that does—and does not—replace.

Open on your device

Choose your operating system for a dedicated step-by-step opening guide.

How to open .DSM files

Use these platform-specific instructions to open .DSM files safely.

Windows

Install and open DeSmuME.
In DeSmuME, use the movie playback option (or the documented command-line option) to play the .DSM movie file.

Full Windows guide

Mac

Install and open DeSmuME for macOS.
Use DeSmuME’s movie playback feature (or its documented command-line option) to open and play the .DSM file.

Full Mac guide

Linux

Install and open DeSmuME for Linux.
Use DeSmuME’s movie playback feature (or its documented command-line option) to load and play the .DSM file.

Full Linux guide

iOS

There is no widely supported, standard way to play DeSmuME .DSM movies on iOS; transfer the file to a desktop system and open it in DeSmuME.

Full iOS guide

Android

There is no widely supported, standard way to play DeSmuME .DSM movies on Android; transfer the file to a desktop system and open it in DeSmuME.

Full Android guide

Security notes

.DSM is a data file consumed by an emulator; while it is not a script or executable, opening untrusted files can still be risky if a parser has vulnerabilities—prefer trusted sources.
Do not assume a .DSM is a video; avoid random “codec/player” downloads claiming to open it—use DeSmuME.
If a .DSM arrives bundled with other files (archives, executables, or unknown installers), treat the bundle with extra caution and only keep what you actually need (the .DSM movie file).

If you did not expect this file

This extension is usually plain data, text, or structured content—not a program by itself. The practical risk is social engineering (a scam attachment or misleading filename). For trusted senders you rarely need heavy-handed antivirus wording; use these tools when you want an extra check on unexpected downloads.

Avast

Avast offers free and premium antivirus software that protects against viruses, malware, ransomware, and phishing. Scan files before opening them to ensure safety.

Norton

Norton 360 delivers comprehensive antivirus protection, VPN, and identity theft monitoring. Scan files for threats before opening to keep your device secure.

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Can't open this file?

These are the most common causes and fixes when .DSM files fail to open.

Common reasons

The .DSM file opens in the wrong app or won’t open
Playback desyncs or does not reproduce the same run
File is corrupt or incomplete

Fix steps

Open DeSmuME first, then use its movie playback function to select the .DSM file.
If double-clicking is required, change the file association to DeSmuME on your desktop OS.

OS-specific troubleshooting

What is a .DSM file?

.DSM most commonly refers to the DeSmuME “movie capture” format (often used for TAS and reproducible gameplay replays). These files record input and related metadata for playback in the emulator, not actual rendered video frames. IANA registers a vendor media type for this format: application/vnd.desmume.movie.

Background

In practice, .DSM files are used by DeSmuME to record and replay emulator “movies” (deterministic input recordings). This is common in tool-assisted speedrunning workflows because it allows a run to be replayed and verified when the same emulator behavior and settings are used.

DeSmuME’s documentation references recording and playing back “dsm format” movies, including command-line options for automation. Technical community references (such as TASVideos) describe the format as a DeSmuME-specific movie capture and discuss that it is structured data for playback, not a normal multimedia container.

Because .DSM is associated with a specific emulator workflow, the most reliable way to use it is to open it in DeSmuME on a desktop OS. If you need a shareable video, you typically play the .DSM in DeSmuME and separately capture/export video using recording tools rather than “converting” the .DSM directly.

Common MIME types: application/vnd.desmume.movie

Common .DSM issues

The .DSM file opens in the wrong app or won’t open

A .DSM is not a normal video file; file managers may associate it with unrelated apps or show it as unknown.

Open DeSmuME first, then use its movie playback function to select the .DSM file.
If double-clicking is required, change the file association to DeSmuME on your desktop OS.

Playback desyncs or does not reproduce the same run

DeSmuME movies depend on emulator behavior and settings; mismatches can cause the replay to diverge from the original recording.

Try playing the movie in the same emulator (DeSmuME) and keep settings consistent with the recording environment.
If available, consult format notes/reference material (for example TASVideos) to understand required conditions for deterministic playback.

File is corrupt or incomplete

If the download was interrupted or the file was modified, DeSmuME may refuse to play it or playback may fail.

Re-download or re-copy the file from the original source.
If you received it via chat/email, ask the sender to re-send the original file without modification.

FAQ

Is a .DSM file a video file I can play in VLC or a media player?

Usually no. A DeSmuME .DSM is a movie/input recording for emulator playback, not a standard video container.

What program opens .DSM files?

Most commonly, DeSmuME opens .DSM files as “DeSmuME Movie capture” recordings.

Can I convert .DSM to MP4?

Not directly like a typical conversion. The common workflow is to play the .DSM in DeSmuME and record/export the resulting video using capture/recording tools.

Is there an official MIME type for DeSmuME .DSM movies?

Yes. IANA lists the vendor media type application/vnd.desmume.movie.

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