How to: Use System Policies to Hide Specific Drives (242092)


The information in this article applies to:

  • Microsoft Windows NT Workstation 4.0
This article was previously published under Q242092

SUMMARY

This article describes how a system administrator can restrict use of drives by 'hiding' one or more drives on a Windows NT-based computer. The System Policy Editor in Microsoft Windows NT Server 4.0 has an Hide drives in My Computer feature that hides all drives from the user. However, you may want to hide only selected drives, while retaining use of other drives.

MORE INFORMATION

To use system policies to hide drives, follow these steps:

  1. Obtain the decimal value for the drives you want to restrict.

    NOTE: The registry key that this policy affects uses a decimal number that corresponds to a 26-bit binary string, with each bit representing a drive letter: 
      11111111111111111111111111
  ZYXWVUTSRQPONMLKJIHGFEDCBA
    This configuration corresponds to 67108863 (in decimal) and hides all drives. If you want to hide drive C, you would make the third lowest bit 0 and then convert the binary string to decimal. The following are sample values that correspond to various drive letters:

    Hide all drive letters (default): 67108863
    Hide all drive letters but C: 67108859
    Hide all drive letters but U: 66060287
    Hide all drive letters but C: and U: 66060283
    Hide all drive letters but C,O, and U: 66043899

  2. Edit the Common.adm file:
    1. Open the Common.adm file in a text editor such as Notepad.
    2. Locate the HideDrives section in the Common.adm file. Note that it should look like the following:
        CATEGORY !!Shell
  CATEGORY !!Restrictions
  POLICY !!HideDrives
  VALUENAME ''NoDrives''
  VALUEON NUMERIC 67108863	; low 26 bits on (1 bit per drive)
  END POLICY
    3. Replace the VALUEON NUMERIC value with your new value.
    4. Save and then close the file.
  3. Edit the system policy:
    1. Click Start, point to Programs, point to Administrative Tools (Common), and then click System Policy Editor.
    2. On the File menu, click Open Registry.
    3. Double-click the Local User policy.
    4. Open the policy to the following location:

      Local User\Shell\Restrictions

    5. Click to select the Hide drives in My Computer check box, and then click OK.

      NOTE: Only the drives that you specified in the VALUEON NUMERIC value in the Common.adm file are hidden.
    6. On the File menu, click Save.
  4. Log off and then log on to the computer for the changes to take effect.
You can also use the Microsoft Zero Administration Kit (ZAK) for Windows NT Server 4.0 to selectively hide files. However, the ZAK method requires modifying the Zakwinnt.adm file to add other drive letter options beyond the five built-in selections. The ZAK method can be implemented using only a Windows NT Server-based computer and the original policy template files (Common.adm and Winnt.adm).
Modification Type:MajorLast Reviewed:8/27/2002
Keywords:kbhowto kbinfo KB242092
©2002 Microsoft Corporation. All rights reserved.