Cannot Access CD-ROM Drive from MS-DOS Mode or Command Prompt

The information in this article applies to:

• Microsoft Windows 95

SYMPTOMS

When you restart your computer in MS-DOS mode or boot to a Windows 95 command prompt from the hard disk or a bootable floppy disk, you may be unable to access the CD-ROM drive. This behavior may occur even though you are able to access the CD-ROM drive from the Windows 95 graphical user interface.

CAUSE

This behavior can occur if the real-mode CD-ROM driver and real-mode Microsoft CD-ROM Extensions driver, Mscdex.exe, (or a third-party equivalent) are not being loaded in the Config.sys and Autoexec.bat files that are used when you restart the computer in MS-DOS mode or boot to a Windows 95 command prompt.

To access a CD-ROM drive when you boot to a Windows 95 command prompt or restart the computer in MS-DOS mode, you must load the real-mode CD-ROM driver in the Config.sys file and the MSCDEX driver in the Autoexec.bat or Dosstart.bat file. If your CD-ROM drive is supported in protected mode in Windows 95, the real-mode CD-ROM and MSCDEX drivers are most likely not being loaded in the Config.sys and Autoexec.bat or Dosstart.bat files on the hard disk. In addition, if you boot from a floppy disk, the CD-ROM and MSCDEX drivers will not load unless you manually configure the Config.sys and Autoexec.bat files on the floppy disk to load them.

RESOLUTION

Make sure that the Config.sys and Autoexec.bat or Dosstart.bat files you use when you restart the computer in MS-DOS mode or when you boot to a Windows 95 command prompt load the necessary real-mode drivers for the CD-ROM drive. Be sure to use the Mscdex.exe file in the Windows\Command folder.

MORE INFORMATION

Windows 95 does not include real-mode CD-ROM drivers. If you need access to the CD-ROM drive when you boot to a Windows 95 command prompt or when you restart the computer in MS-DOS mode, you must use the real-mode CD-ROM driver included with the CD-ROM drive. For information about how to obtain, install, or configure the real-mode CD-ROM driver, consult the documentation included with the drive, or contact the drive's manufacturer.

Windows 95 does include an MSCDEX driver that is located in the Windows\Command folder. If you must use a real-mode MSCDEX driver, you should use the driver in the Windows\Command folder instead of the driver included with the CD-ROM drive.

The real-mode CD-ROM and MSCDEX drivers can be loaded from several different locations, depending on the reason they are being loaded. If you are loading the real-mode drivers because you need access to the CD-ROM drive when you boot to a Windows 95 command prompt, the drivers must be loaded from the Config.sys and Autoexec.bat files in the root folder of the boot drive. If you are booting to a Windows 95 command prompt from a floppy disk instead of a hard disk, the drivers must be loaded from the Config.sys and Autoexec.bat files on the floppy disk.

If you are loading the real-mode drivers because you are restarting the computer in MS-DOS mode, the drivers can be loaded from either of the following locations:

• The Config.sys and Autoexec.bat files in the root folder of the boot drive.
• The custom Config.sys and Autoexec.bat files that you specify in the properties for the program you are running in MS-DOS mode, the properties for a shortcut that starts the program you are running in MS-DOS mode, or the properties for the "Exit to Dos.pif" file that is used to start Windows 95 in MS-DOS mode.

NOTE: When you install Windows 95, Setup disables (remarks out) the existing Mscdex.exe line in the Autoexec.bat file if it detects a CD-ROM drive for which Windows 95 includes a protected-mode driver. Therefore, when you boot to a command prompt or restart the computer in MS-DOS mode, MSCDEX is not available. To make MSCDEX available, enable the existing Mscdex.exe line in the Autoexec.bat file. You may also need to modify the line so that it loads the MSCDEX driver from the Windows\Command folder instead of the driver included with the CD-ROM drive.