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DOSBox-X emulates a complete CD-ROM drive, including the Microsoft MSCDEX extension that DOS programs expect. You can mount an ISO image, a CUE/BIN disc dump with audio tracks, a folder of files, or even a physical CD-ROM drive on Windows — and the game will behave as if a real optical drive is connected. No separate MSCDEX.EXE driver is needed; DOSBox-X provides it internally.

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Mounting Methods

There are four ways to mount a CD-ROM in DOSBox-X, each suited to a different situation:
1

Mount an ISO image file

An .iso file contains the data tracks of a disc. Most modern CD backups are in this format.
IMGMOUNT D C:\game.iso -t cdrom
On Linux or macOS:
IMGMOUNT D ~/games/game.iso -t cdrom
2

Mount a CUE/BIN image (with audio tracks)

A .cue sheet describes the track layout of a disc; the actual data lives in an accompanying .bin file (or separate audio files). Always point IMGMOUNT at the .cue file, not the .bin.
IMGMOUNT D C:\game.cue -t cdrom
DOSBox-X reads the CUE sheet to locate every track, including CD audio. Using the .bin directly instead of the .cue means audio tracks will be silent.
3

Mount a physical CD-ROM drive (Windows only)

Pass the host drive letter as the image path to tunnel a real optical drive through the emulator.
IMGMOUNT D D: -t cdrom -fs iso
Replace the second D: with the actual Windows drive letter of your physical drive.
4

Mount a folder as a simple CD-ROM

When you have a directory of files extracted from a disc and do not need audio playback, mounting with -t cdrom makes DOS treat the folder as an optical drive. Write operations will be blocked.
MOUNT D C:\cdfiles -t cdrom
The drive letter you choose for your CD-ROM is typically D: or E:. Some games hard-code a specific letter; check the game’s manual or README if it cannot find its disc after mounting.

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CD-DA Audio Track Support

Many DOS games ship on mixed-mode CDs where the first track holds data and the remaining tracks hold Red Book audio. DOSBox-X supports these discs through its built-in SDL_Sound decoder library. Audio tracks referenced in a CUE sheet can be stored in any of the following formats:

BINARY (.bin)

Raw 16-bit PCM interleaved stereo, as found in a standard CUE/BIN rip. This is the original Red Book format and has the best compatibility.

MP3 (.mp3)

Compressed audio tracks. DOSBox-X includes its own MP3 decoder; no external library is required.

OGG Vorbis (.ogg)

Open-source compressed audio. Widely used in re-releases where audio has been re-encoded from the original disc.

FLAC (.flac)

Lossless compressed audio. Produces the best audio quality and still reduces file size versus raw .bin tracks.

WAV (.wav)

Uncompressed PCM in a container. Equivalent in quality to .bin but slightly larger due to the WAV header.

Opus (.opus)

Modern low-bitrate codec. Supported via DOSBox-X’s built-in Opus decoder.

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CUE Sheet Format

A CUE sheet is a plain-text file that describes disc structure. Here is an example showing a data track followed by two audio tracks — one stored as raw binary and one as an MP3 file: 
FILE "game.bin" BINARY
  TRACK 01 MODE1/2048
    INDEX 01 00:00:00

FILE "track02.bin" BINARY
  TRACK 02 AUDIO
    INDEX 00 00:00:00
    INDEX 01 00:02:00

FILE "track03.mp3" MP3
  TRACK 03 AUDIO
    INDEX 01 00:00:00
Always mount via the .cue file, never the .bin directly. If you point IMGMOUNT at a .bin, DOSBox-X treats the whole file as a single data track and audio will not play.
Other supported CUE file types for audio track references include WAVE, OGG, FLAC, and OPUS. The keyword in the CUE FILE line should match the format of the audio file being referenced.

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Built-in MSCDEX Emulation

Real DOS systems required loading a CD-ROM extension driver (MSCDEX.EXE from Microsoft, or equivalent) before the OS could access optical drives. DOSBox-X emulates MSCDEX automatically whenever a drive is mounted with -t cdrom or as an ISO image. You do not need to include MSCDEX.EXE in your [autoexec] section or CONFIG.SYS. Programs that check for MSCDEX will find it present and functional. The emulated MSCDEX responds correctly to drive information queries, audio playback commands, and multi-volume queries.

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Swapping Disc Images at Runtime

Multi-disc games prompt you to insert a different disc during play. DOSBox-X handles this without ejecting anything physically.
When you mount multiple image files at once, Host+D (by default F11+D on Windows or F12+D on Linux/macOS) cycles through them in order. Each press advances to the next image in the list.
REM Mount three discs as a swap list
IMGMOUNT D C:\disc1.iso C:\disc2.iso C:\disc3.iso -t cdrom
When the game asks you to insert disc 2, press Host+D once. Press again for disc 3, and once more to return to disc 1.

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Eject and Insert Emulation

DOSBox-X emulates tray open/close operations at the hardware level. Some copy-protection schemes and CD audio players test whether a disc is present by attempting to open and close the drive tray.
  • Drive → Eject — Emulates opening the tray (disc removed).
  • Drive → Insert — Emulates closing the tray (disc inserted).
You can also eject and re-insert to force the drive to re-read the current disc, which is occasionally needed after swapping images via the menu.

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CD Audio Playback Tips

You are almost certainly mounting an .iso file for a game that originally shipped with audio tracks. An ISO rip captures only the data track. You need to remount using the .cue file from a proper CUE/BIN rip of the same disc. If you only have the ISO, there is no audio data to play back.
CD audio is decoded in real time. Lower the CPU cycles in DOSBox-X — press Host+Minus (default: F11+Minus on Windows, F12+Minus elsewhere) to lower cycles — to ensure the audio decoder keeps up. You can also try mounting with a raw .bin track instead of a compressed format to reduce decoder overhead.
The CD audio mixer channel (CDAUDIO) is created dynamically when a disc with audio tracks is mounted and the game first requests audio playback. It does not appear until audio is actually triggered by the running program.
Confirm you are using the Windows build of DOSBox-X and that the correct host drive letter is passed as the second argument to IMGMOUNT. Windows 10 and 11 may require running DOSBox-X as administrator to allow raw drive access through IOCTL.

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Quick Reference

REM ISO image (data only)
IMGMOUNT D C:\game.iso -t cdrom

REM CUE/BIN image (data + audio)
IMGMOUNT D C:\game.cue -t cdrom

REM Physical drive on Windows (host drive is D:, assign as E:)
IMGMOUNT E D: -t cdrom -fs iso

REM Folder mounted as CD-ROM (read-only, no audio)
MOUNT D C:\cdfiles -t cdrom

REM Swap list for a multi-disc game
IMGMOUNT D C:\disc1.cue C:\disc2.cue C:\disc3.cue -t cdrom

REM Unmount the CD-ROM drive
IMGMOUNT -u D

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