Microsoft KB Archive/169620

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Err Msg: Accessing CD-ROM Drive: D:\ Is Not Accessible

Article ID: 169620

Article Last Modified on 10/31/2006


  • Microsoft Windows NT Workstation 4.0 Developer Edition
  • Microsoft Windows NT Server 4.0 Standard Edition

This article was previously published under Q169620


Windows NT is installed using WINNT /B on a computer using either EIDE controllers and IDE drives, or a SCSI controller and IDE or SCSI drives, without an attached IDE CD-ROM drive. At a later time, an ATAPI 1.2- compliant IDE CD-ROM drive is attached to the system, and Windows NT recognizes the CD-ROM drive in both Disk Administrator and Windows Explorer with an assigned drive letter. When the user tries to access the CD-ROM drive using Windows Explorer, the user receives one of two error messages:

D:\ is not accessible.

The volume does not contain a recognized file system. Please make sure that all required file system drivers are loaded and that the volume is not corrupt.


From a Windows NT MS-DOS command prompt:

The System cannot find the drive specified.


This problem occurs because the CD-ROM file system (CDFS) registry entries are not properly initialized during Setup when a CD-ROM drive is not attached.


WARNING: Using Registry Editor incorrectly can cause serious, system-wide problems that may require you to reinstall Windows NT to correct them. Microsoft cannot guarantee that any problems resulting from the use of Registry Editor can be solved. Use this tool at your own risk.

  1. Start Registry Editor (Regedt32.exe).
  2. Go to

  3. On the Registry menu, click Save key and call it 000.reg.
  4. Go to

  5. Click the 0000 key, and then click Permissions on the Security menu.
  6. Change the 0000 key permissions to Everyone : Full Control, and then click OK.
  7. On the Registry menu, click Restore, and restore the 000.reg key saved from step 3 on top of the current 0000 key under Legacy_cdfs.
  8. Under the restored 000 key, modify the following two entries:
    1. Change DeviceDesc:REG_SZ:Cdrom Device to Cdfs Device.
    2. Change Service:REG_SZ:Cdrom to Cdfs.
  9. Exit Regedt32.exe and then restart Windows NT. The CD-ROM drive should now work normally.


Microsoft has confirmed this to be a problem in Windows NT version 4.0. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

Keywords: kbbug kbhardware kbsetup KB169620