What is the MDS file format?
.mds files are informational sidecar files that contain data describing the layout and formatting of CD and DVD disc images. Data stored in .mds files depict the track arrangement, header metadata, and copy-protection structure of the original disc. This includes information such as image size, session boundaries, sector modes, and other disc-level parameters.
.mds files do not contain any sector data - the actual audio, video or data content is stored in the companion .mdf file of the same base name. The function of an .mds file is only to describe and reference that paired data. Before mounting or burning, the application reads the .mds descriptor to reconstruct the original disc structure and then loads the appropriate image data.
Every .mds file begins with the ASCII signature MEDIA DESCRIPTOR at byte offset 0, which disc emulation tools use to identify and validate the format. Developed by Alcohol Soft for Alcohol 120% in the early 2000s, the format was later adopted by DAEMON Tools and is widely supported by virtual drive and burning software on Windows.
.mds files can be used with disc image programs to burn content back to physical CD or DVD media. The .mds/.mdf pairing is conceptually similar to the .cue/.bin pair used in other disc image workflows - one file describes the disc, while the other holds the raw sector data.
Security & safety
RISK: MEDIUMThe format itself is inert data. The real risk is that MDS/MDF images are a classic delivery method for pirated games and software, which frequently bundle malware, fake 'keygens' or cracks - scan any downloaded .mds/.mdf with up-to-date antivirus before mounting, and be wary of images that insist you disable your AV or run an installer. Mounting an image is generally safe; running unknown executables from inside it is the danger.
Format details
in a nutshellPrograms that open MDS files
Windows6 apps
IsoBuster
Freemium Open the .mds to browse and extract individual files/tracks; strong for damaged or unusual images. 
AnyToISO
Freemium Convert the MDS/MDF pair to a single .iso in one step for native Windows mounting. 
DAEMON Tools Lite
Freemium Mount the .mds (with its .mdf in the same folder) as a virtual drive - Windows then treats it like an inserted CD/DVD.
Alcohol 52% Free Edition / Alcohol 120%
Freemium Mount or burn the image - this is the program that created the format. Note: last release 2.1.1 (Dec 2022), minimal updates since. 
macOS1 app
Linux2 apps
PowerISO (Linux CLI)
Paid Use the poweriso command-line tool to convert/extract the MDS/MDF image (e.g. to ISO).
bchunk / iat (image tools)
Open-source Convert the raw image to ISO/BIN+CUE so it mounts with a loop device; install via your distro's package manager. Technical details
deep spec| File structure | Binary; not human-readable |
| File signature (magic bytes) | `MEDIA DESCRIPTOR` (hex `4D 45 44 49 41 20 44 45 53 43 52 49 50 54 4F 52`) at byte offset 0 |
| MIME type | `application/octet-stream` |
| Companion file | Always paired with an `.mdf` file of the same base name that holds the raw sector data |
| Developer | Alcohol Soft (Alcohol 120%); adopted by DAEMON Tools (Disc Soft) |
| Typical file size | A few kilobytes - descriptor only; all sector data lives in the paired `.mdf` |
| Disc types supported | CD-ROM, CD-Audio, CD-R/RW, DVD-ROM, DVD±R/RW, mixed-mode and multi-session discs |
| Sector mode encoding | Records sector size and mode per track: Mode 1 (2048 B), Mode 2 Form 1/2 (2336-2352 B), raw audio (2352 B) |
| Copy-protection metadata | Stores protection scheme descriptors (SafeDisc, SecuROM) to enable accurate virtual-drive emulation |
| Subchannel data support | Can reference Q-channel and raw subchannel data required for copy-protected disc emulation |
| Naming convention | Base name must match the companion `.mdf` (e.g., `image.mds` paired with `image.mdf`) |
| Primary platform | Windows; cross-platform tools (IsoBuster, AnyToISO, PowerISO CLI) also read the format on Linux and macOS |
| Relation to ISO images | Not interchangeable with `.iso`; the `.mdf`/`.mds` pair preserves subchannel and copy-protection data that plain ISO cannot |
| Mounting and burning | The `.mds` is loaded first; the application then mounts or burns the paired `.mdf` sector data |
| Analogous formats | Functionally similar to the `.cue`/`.bin` pairing and Nero's `.nrg` single-file format |
| Released | Early 2000s (Alcohol 120%) |
MDS conversions
Community Q&A
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