How to Open MDS File on Windows 11, Mac & Linux (MDF/MDS Disc Images)

What is an MDS file?

An MDS file (Media Descriptor Sidecar) is the descriptor half of an MDF/MDS disc image created by Alcohol 120%, Alcohol 52% or DAEMON Tools. It's a small binary file, usually a few kilobytes, that records how the original CD or DVD was laid out: the disc type, the sessions, each track's type and position, and the name of the data file. The disc's actual contents are in the companion .mdf (Media Disc image File), which is the big file, roughly the size of the disc.

The format comes from Alcohol 120%, Alcohol Soft's disc imaging program first released in October 2002. Unlike a basic ISO, an MDF/MDS image can hold several tracks, audio tracks next to data (Mixed Mode CDs), multiple sessions and dual-layer DVDs, and the .mds can store extra measurements that some copy-protected discs check. That's why game backups from the 2000s were often shared as MDF/MDS pairs, and why you can't open MDS files with a text editor or a ZIP program.

Other files that use the .mds extension

Almost every .mds you'll meet is a disc descriptor, but two programs reuse the extension. The checker above tells them apart, because a disc descriptor always starts with the text MEDIA DESCRIPTOR.

And beware the opposite mix-up: a big .mdf without any .mds can also be a Microsoft SQL Server database, since .mdf is SQL Server's recommended extension for primary data files. Those open in SQL Server, not in a disc tool; the checker says which one you have.

How to open an MDS file: quick answer

To open MDS files, you mount them as a virtual CD/DVD drive. Windows and macOS can't do this on their own for this format, so you need a small free program:

1. Put both files in one folder with the same name, for example game.mds and game.mdf.
2. Install a mounter: DAEMON Tools Lite or WinCDEmu on Windows, DAEMON Tools for Mac, or CDEmu on Linux.
3. Double-click the .mds (not the .mdf), or right-click it and choose the mount command.
4. Open the new drive in File Explorer or Finder and use the disc as if it were inserted: browse files, run setup, play the video.

Open MDF/MDS files on Windows 11 and 10

Windows 11 and 10 can't mount MDS images natively: the built-in Mount command (and PowerShell's Mount-DiskImage) handles only ISO, VHD and VHDX files. Double-clicking an .mds without extra software just asks which app to use. To open MDS files on Windows, pick one of these free mounters:

With DAEMON Tools Lite

1. Install DAEMON Tools Lite from the official site, daemon-tools.cc.
2. In File Explorer, double-click the .mds. You can also click Quick Mount in the program window and pick the .mds, or drag it onto the virtual devices area.
3. Open This PC: the image appears as a new DVD drive. Drives are unmounted automatically when you restart, by default.

With WinCDEmu

1. Install WinCDEmu from wincdemu.sysprogs.org.
2. Double-click the .mds, or right-click it and choose Select drive letter & mount.
3. Click OK. To unmount, right-click the virtual drive and choose Eject, or double-click the .mds again.

Once mounted, the disc behaves like any DVD drive. For a game, run setup.exe or autorun.exe from the drive. For a movie DVD, open the drive's VIDEO_TS folder with a DVD-capable player (see how to play VOB files).

Open MDS files on Mac

macOS's Disk Utility doesn't recognize MDF/MDS images, so to open MDS files on a Mac use one of these:

• DAEMON Tools for Mac lists .mds, .mdf and .mdx among the image types it works with. Mount the .mds and the disc appears in Finder.
• AnyToISO (Crystalidea, Windows and macOS) converts an MDF image to a standard ISO, which macOS then mounts with a double-click. Pro licenses cost $29.95 for Windows & macOS at the time of writing.
• mdf2iso (free, command line) installs with MacPorts: sudo port install mdf2iso, then mdf2iso game.mdf. See converting.
• The checker on this page: if your .mdf is already a plain ISO (common for DVD images), it gives you an .iso copy with no software at all.

Open MDS files on Linux

CDEmu is the native way to open MDS files on Linux. Its libMirage library reads Alcohol 120% MDS images and DAEMON Tools MDX images, audio tracks and multiple sessions included, and presents them as a real virtual SCSI CD/DVD drive. Install it from your distribution's packages or the CDEmu website, then load the image by its .mds:

If you'd rather not open MDS file pairs with a virtual drive at all, mdf2iso (in Debian and Ubuntu as mdf2iso) turns the .mdf into an ISO, or with --cue into a BIN/CUE pair, or with --toc into a TOC/DAT pair. Note that it reads the .mdf, not the .mds.

iPhone, iPad and Android

You can't usefully open MDS files on a phone or tablet: they have no virtual CD/DVD drive, and MDF/MDS images almost always hold PC software or games, so there's nothing useful to mount on mobile. What you can do on a phone is check the files before copying them to a computer: the checker runs in mobile Safari and Chrome, shows what disc the .mds describes and whether the .mdf is complete. If the image is a plain ISO, its .iso copy can be opened by mobile archive apps; see how to open ISO files.

Convert MDF/MDS to ISO (and when you shouldn't)

Converting works well for single-track data discs, which is most DVD images and many software CDs. An ISO stores only 2,048-byte data sectors from one track, so it can't hold CD audio tracks, multiple sessions, subchannel data or copy-protection measurements. AnyToISO's own FAQ says audio CD images can't be converted to ISO for this reason.

Three ways to convert

1. No install: drop the .mds and .mdf into the checker. If the .mdf is a plain ISO, save it as .iso. If it's a raw CD image, download the CUE sheet instead: tools that read BIN/CUE images then use the .mdf directly, nothing converted.
2. AnyToISO (Windows, macOS): drag the .mdf into AnyToISO's window and start the conversion to ISO. Pro licenses start at $22.95 for Windows at the time of writing.
3. mdf2iso (Linux, macOS): mdf2iso game.mdf writes game.iso; --cue writes BIN/CUE instead.

Once you have the ISO, Windows 11 and macOS mount it with a double-click; see our ISO guide for that and for making a bootable USB.

MDS without MDF, or MDF without MDS

"I only have the .mds"

Then you don't have the disc. An .mds is usually just a few kilobytes because it holds only the table of contents; every file from the disc lives in the .mdf. No program can mount, extract or convert an .mds alone. Look for the .mdf in the same download, archive or backup folder (it may have been split into a multi-part RAR or ZIP; extract every part, see opening RAR files).

"I only have the .mdf"

That's often fixable, because the .mdf has the data. Drop it into the checker:

• Plain 2048-byte sectors with an ISO 9660 or UDF file system (most DVD images): save it as .iso and open it like any ISO.
• Raw 2352-byte CD sectors: download the generated CUE sheet and mount the .cue with WinCDEmu, DAEMON Tools or CDEmu. It assumes one data track, so a game's CD music will be missing; find the original .mds if that matters.
• 2448-byte sectors (with subchannel): only the original .mds will do, because this is a copy-protected disc image.
• No disc data at all: the file is probably a SQL Server database (.mdf), not a disc image.

Burn or play an MDF/MDS image

To burn the image to a blank CD or DVD, use ImgBurn's Write mode and select the .mds file; ImgBurn lists MDS among the image formats it writes. Use a blank disc of the same type as the original (CD-R for a CD image, DVD+R DL for a dual-layer DVD), which the checker shows as Disc type.

1. Open ImgBurn and choose Write image file to disc.
2. Click the folder icon under Source and select the .mds.
3. Insert a blank disc and click the Write button.

ImgBurn's last release is 2.5.8.0 from June 2013 and its site lists Windows up to 10, but it remains a common choice for this job. To play an image, you don't need to burn it: mount the .mds as shown above, then play the virtual drive like a real disc.

MDS vs CUE vs ISO vs MDX

All four describe a disc image; they differ in what they can keep from the original disc and in which programs read them.

MDX is DAEMON Tools' own format: the descriptor and all the disc data in one file, with optional compression. DAEMON Tools also writes version 2 .mds files whose descriptor is compressed and encrypted, unlike Alcohol's version 1 files. Both open in DAEMON Tools and CDEmu; readers built for version 1, such as the open-source Aaru, don't support them. The checker above shows which version you have. For the plain-text alternative, see the CUE file guide.

Common MDS problems and how to fix them

"Unable to find the MDF file" or "file not found"

The mounter read the .mds but couldn't find its data file. Most .mds files store the name as *.mdf, which means "same name as me", so Game.mds looks for Game.mdf in the same folder. If you renamed one file, rename the other to match. Some descriptors store an exact name such as Backup Disc.mdf; the checker's Overview shows it, and the .mdf must carry that exact name.

The image mounts but the drive is empty or unreadable

Usually the .mdf is incomplete (an interrupted download or a missing archive part). Drop both files into the checker: it compares the .mdf's size with what the tracks need and reports exactly how many bytes are missing. An incomplete .mdf can't be repaired; download or copy it again.

"Unsupported format" or "invalid image"

You probably have a DAEMON Tools .mdx or a version 2 .mds, which programs written for Alcohol's version 1 layout may not read. Open MDS files of that kind in DAEMON Tools Lite (Windows), DAEMON Tools for Mac or CDEmu (Linux).

Opening the .mds in Notepad shows gibberish

That's normal: an .mds is binary, not text, so you can't open MDS file contents as a document. Use the viewer above to read its contents in plain English.

The game says "insert the original disc"

Some copy-protected games check physical traits of the original disc. Images that kept those traits have 2448-byte sectors or DPM data (the checker flags both), and they need DAEMON Tools or Alcohol, not an ISO. Even then, protection can refuse virtual drives; that's the protection working, not a damaged image.

Windows asks "How do you want to open this file?"

No mounter is installed, or another program took over the .mds association. Install DAEMON Tools Lite or WinCDEmu, or right-click the .mds > Open with and pick it.

Is an MDS file safe? Can I delete it?

Yes, it's safe to open MDS files: an .mds is a data table that a mounting program reads, and it can't run anything. Treat the disc inside the .mdf like any downloaded software, though: scan it with your antivirus and run installers only from sources you trust.

Can you delete it? Keep the .mds as long as you want to mount the image, because many mounters need it. If the checker shows the .mdf is a plain ISO and you've saved the .iso copy, the .mds and .mdf are no longer needed. For CD images with audio tracks, keep the pair: the .mds is the only record of where the tracks start.

What's inside an .mds file (technical)

The format is proprietary and undocumented; what's known comes from reverse engineering, implemented in the open-source libMirage (CDEmu) and Aaru projects. Every version 1 .mds is little-endian and starts with an 88-byte header. This is the layout the checker decodes when you open MDS file descriptors with it:

Track mode bytes such as 0xA9 (audio, 2,352-byte sectors), 0xAA (Mode 1) and 0xAC/0xAD (Mode 2 Form 1/Form 2) are decided by their low four bits. Version 2 files (DAEMON Tools) keep the same kind of data, but the descriptor after a 48-byte header is zlib-compressed and AES-256 encrypted, which is why the checker identifies them but can't list their tracks.

Related file extensions

Sources and technical references

The MDS format is proprietary and undocumented by its developer, so the structure above comes from open-source implementations; program features come from each developer's own pages, checked on October 7, 2026.

• Media Descriptor File — Wikipedia — MDF/MDS origin in Alcohol 120%, multi-track and dual-layer support.
• libMirage MDS structures (image-mds.h) — CDEmu on GitHub — header, session, track and footer layouts, medium and track-mode codes.
• libMirage MDX / MDS v2 structures (image-mdx.h) — version 2 header and encrypted descriptor.
• Aaru Alcohol 120% image plugin (Structs.cs) — independent implementation of the same structures.
• libMirage supported formats — CDEmu and cdemu(1) manual — MDS/MDX support and the cdemu load command.
• Alcohol 120% — Wikipedia — developer, October 2002 release, Alcohol 52% limits.
• DAEMON Tools — Wikipedia — MDX as a single-file format with compression.
• DAEMON Tools Lite — product page, mounting help and Mac file types.
• WinCDEmu — Sysprogs and its mounting tutorial.
• Mount-DiskImage — Microsoft Learn — Windows' built-in mounting covers ISO, VHD and VHDX.
• mdf2iso(1) — Debian manpages and mdf2iso on MacPorts.
• Convert MDF to ISO — Crystalidea (AnyToISO), AnyToISO FAQ and pricing.
• ImgBurn — supported image formats (including MDS), version 2.5.8.0.
• ISO 9660 — OSDev Wiki — volume descriptor at sector 16 and the volume label field the checker reads.
• TestComplete project files (.mds) — SmartBear, FileInfo .mds entry and SQL Server database files (.mdf).

Frequently asked questions