Restoring Dos Ability to Windows Millennium

Has Real-mode DOS been removed
from Microsoft’s Windows ® Millennium Edition?

We’ve been asked this same question many times recently as beta testers review pre-release versions of Windows ME and more and more information leaks out to the general public. Well, the answer is No, Real-mode DOS has not been removed from Windows. Well hidden maybe, and removed from the boot process, but it’s still there.

Windows ME is still DOS based like its predecessors, but in an effort to speed up the startup process Microsoft has restructured some of the files necessary to allow you to boot to DOS, use config.sys and autoexec.bat files and view and use a boot menu.

We have a patch that will modify your “IO.SYS”, “COMMAND.COM” and “REGENV32.EXE” files in order to unhide the real-mode DOS in Windows ME systems, thereby providing you with a boot process like that of previous versions of Windows. This will allow you, for example, to reach the DOS boot menu directly by pressing “Shift-F8” at boot-up, and to use “CONFIG.SYS” and “AUTOEXEC.BAT” as part of the startup process before Windows loads. This patch was tested only with the final release of Win ME (build 4.90.3000) and may not be compatible with other pre-release versions.


As stated above, this has only been tested on Windows ME version 4.90.3000 U.S. If you are using a Non-US version of Windows ME this patch may not work and may even cause problems.

Installation Procedure

In order to install this patch correctly, please follow the instructions below explicitly!

While these particular instructions refer to “C:\Windows”, you should use the specific directory on your computer into which Windows ME was originally installed.

Step One: (This can be done in Windows using Windows Explorer)

  1. Create two temporary directories on your hard drive such as C:\Temp and C:\Dos_Storage and make sure that both are empty.

  2. Download the patch ( and unzip the 5 included files into the C:\Temp directory. You should have these 5 files:

    • autoexec.bat
    • config.sys
    • File_id.diz
    • Mfd.nfo

  3. Copy the following original Windows ME files into both the C:\Temp and C:\Dos_Storage directories. Their location is already noted for you.

    • C:\Windows\COMMAND.COM
    • C:\Windows\Command\EBD\IO.SYS (See the “Notes” below, #4)
    • C:\Windows\System\REGENV32.EXE

  4. Now you will need to make sure that the “R”, “H” and “S” attributes have been removed from the 3 files noted above in only the C:\Temp directory. You can do this from within Windows Explorer by right clicking on each file and choosing “Properties”, then uncheck any of the attribute boxes, “Read-only”, “Hidden” and “Archive”, that may be checked and then click “Apply” and then close the box.

  5. Next, using Windows Explorer, locate the “WINMEDOS.COM” file from the ( you downloaded and unzipped earlier.

    Double click on “WINMEDOS.COM” to execute it. Do not move to step two unless you are certain that patch completed successfully.

Step Two:

Once the patch completes successfully, perform the following tasks in order to complete the installation:

  1. Copy the following 3 patched files back to their original locations as noted below, overwriting the originals.
    • Copy “IO.SYS” from the C:\Temp directory to “C:\”

    • Copy “COMMAND.COM” from C:\Temp to “C:\WINDOWS\”

    • Copy “COMMAND.COM” from C:\Temp “C:\”

    • Copy “REGENV32.EXE” from C:\Temp to “C:\WINDOWS\SYSTEM”
  2. Next, copy the Config.sys from C:\Temp to C:\
    and the Autoexec.bat from C:\Temp to C:\


1.  The Config.sys contained in the file contains only this line:


You may add any other lines to your Config.sys file as long as the above line remains.

2.  The Autoexec.bat contained in the file contains only this line:


You may add any other lines to your Autoexec.bat file as long as the above line remains.

3.  In the event that you wish to create a startup menu that will permit you to choose between Windows and MS-DOS at startup, it can be done by editing your “Config.sys” and “Autoexec.bat” files. The syntax of the startup menu is identical to the syntax on Win 9x systems.

Keep in mind that the option configured to launch Win ME has to include the appropriate lines that load “IFSHLP.SYS” and run “WIN.COM” as noted above.

4.  At startup you will see “Starting Windows Emergency Boot”. This can be ignored as the patch uses  the IO.SYS provided with the Windows ME Emergency Boot Disk. If you have a problem initially with the function of the DOS boot, replace the IO.SYS file as noted above with the one on your Windows ME Startup Boot Disk. During testing, we noted that on occasion the File Protect features built into Windows ME replaced this file during the boot process.

5.  Remember! You saved copies of your original files to the C:\Dos_Storage folder you made at the beginning of this feature. To return your system to its original state, copy the 3 changes files from this directory back to their original directories and remove the Autoexec.bat and Config.sys files from the root of your C:\ drive.

Disclaimer: We make no warranty of any type or kind with respect to this patch and its use by you or anyone else. Making this change will alter the way your operating system starts and, if done incorrectly, could render your operating system unusable!

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