Table of Contents

Installation and Run

System Requirements   Activation   Settings   Languages     Windows   Linux   MacOS   DOS  

Attention! If a device has physical problems (input-output errors, slow performance, etc.) it is recommended to address to specialists - see Working with Failing Devices. If the device is not accessible or has incorrect size see also System Requirements.

Attention! Do not write anything to the disk containing lost data. Recover data to a different disk, as well load operating system, run the software from a different disk, otherwise the data may be erased irrevocably.

It is highly recommended to work in a system which has minimal disk access (especially in write mode). You can create a DOS bootable disk (to clone disks available in IDE mode), or use bootable LiveCD/USB disks based on Linux or special environment like WinFE based on Windows, where disk access is minimized.

For the most compliance with such environment it is recommended to turn off the "fast boot" option and turn on the "USB legacy" mode in your BIOS/UEFI. To boot from the Live disk you may also need to turn off Secure Boot and UEFI mode (switch to Legacy BIOS mode).

To install/reinstall and run the program just extract the entire software package into a single directory (it can be on a removable media) and run dmde.exe or dmde. You need Administrator / Superuser priveleges to access devices in Windows NT+, Linux, macOS. To run the software without Administrator rights add the parameter notadmin=1 to the file dmde.ini. Updates are performed in the same way.

To uninstall the software just remove the extracted files and directories.

Operating Systems

Windows Vista/7/higher

In case of SmartScreen request click "More Info" and confirm the software launch.
To run the program as Administrator use right-click menu on the application icon or confirm UAC elevation request.
Attention! To work with drives larger than 2TB the most recent versions of controller drivers must be installed.

Windows 2K/XP

To use the program you should login as Administrator.
Attention! To work with 128GB and larger drives you need Windows 2K SP4 with LBA48 support manually switched on in the registers or Windows XP SP2 (LBA48 is switched on by default).

Windows 98/ME

Attention! Without special patches Windows 9x/ME handles 128GB and larger drives incorrectly.
To avoid the problem reload computer in MS-DOS mode and use DMDE for DOS to access such drives via BIOS or ATA-interface or load another OS.


At first go to the Root Terminal or run Terminal emulator (Konsole, Gnome-terminal, etc.). Go to the software directory and type ./dmde. You should run the software as a superuser to access devices. Please, refer to your operating system documentation for this information (e.g., run sudo ./dmde in Ubuntu, go to root with su command in Debian at first, etc.). You may also need to set execution permission for the file dmde (type chmod 755 ./dmde). To run 32-bit software versions on 64-bit operating systems you may have to install additional 32-bit shared libraries (e.g., run sudo apt-get install libc6-i386 in Ubuntu to install libc6-i386 package).


Since the modern macOS versions try preventing direct disk access and are less suitable to work with failing drives it is recommended to use different OS's. If there is no different PC you can try to create and load Ubuntu LiveUSB by the instruction.

In macOS you can try to unmount the disk using the system's Disk Utility to gain access. If macOS prevents disk access you may need to turn off the partition tables in a different OS (use commands MBR Off / GPT Off in DMDE in the Partitions window).

If macOS blocks the application running you can use Control-Click or go to System Preferences, choose Security & Privacy and click "Open anyway" for the blocked application: Safely open apps on your Mac

It is also possible to run the software as a root user from terminal, refer to the Linux instructions above.

MacOS specially marks applications got from the Internet and runs them from a randomized directory. In such case the software cannot run portable and uses the user default application support directory for keeping settings and keys. To make application portable run the command in the terminal
xattr -r -d /<path to the app>/
or simply move the directory containing the app and dmde.ini file to a media not supporting extended attributes (i.g. to a FAT formatted USB flash drive).


If there are problems with video ouput you may need to change the value of the parameter biosoutput=0 in the file dmde.ini into: biosoutput=1

If an error occurs when starting the software, there may be a problem with an extended memory manager. Try using the old memory manager by running the batch file dmde_dpo.bat however less memory will be available.

You may use DMDE on a regular partition supported by DOS or use DOS bootable disk. This can be helpful when there are problems using specific disk. SATA disks must be switched to IDE-compatible mode in BIOS settings for direct ATA-access. SCSI, USB, and other devices can be accessed via special DOS drivers or using BIOS functions if they are supported.

Some files for creating DOS boot disks are available on the software site in the section Additional Downloads.

Bootable Floppy

To create bootable floppy download and unpack FDD image. You may use the function Copy Sectors to write the image to a floppy disk. Use the image as a source file and fdd as a destination device. ISO images for bootable CD may also be created on the base of boot FDD images with the help of different software.

DOS Bootable Disk

Loading from the specific disk must be supported by BIOS (see BIOS boot menu). To create bootable USB/HDD you need a freshly formatted primary FAT16/FAT32 partition on the disk. Non-standard disks/partitions are not supported (non-MBR, 3TB+, etc.).

0. For the most compatibility optionally first zero out the disk, then initialize disk as MBR and create and format a primary FAT partition using standard OS means (Windows Disk management).
1. Download the FreeDOS Package (the site section "Additional downloads") and extract all package files directly to the root directory of the FAT partition.
2. Open the disk as physical device in DMDE and use the command Write Boot Sectors... in the Partitions menu to make the device bootable (specify the root directory on the disk as a source of boot sectors upon the subsequent request). Apply changes and close DMDE.
3. Download DMDE for DOS and unpack into the FAT partition.
4. Use BIOS boot menu / BIOS setup to boot from the specified disk. On modern UEFI systems you may need to enable BIOS legacy mode, turn off secure boot option, switch USB and other devices to legacy modes.