Defining Local and Remote Drive Visibility Under WinNT 4.0

 Last reviewed: May 30, 1997
Article ID: Q158457
The information in this article applies to:
  • Microsoft Windows NT Workstation version 4.0
  • Microsoft Windows NT Server version 4.0

SUMMARY

Windows NT 4.0 administrators can define drive visibility on a per-drive basis by using the NODRIVES entry in the registry.

MORE INFORMATION

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.

The NODRIVES entry (reg_dword) located in 

   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies
   \Explorer
uses a 32-bit word to define local and network drive visibility for each logical drive in the computer.

The lower 26 bits of the 32-bit word correspond to drive letters A through Z. Drives are visible when set to 0 and hidden when set to 1. Drive A is represented by the rightmost position of the bitmask when the radix is viewed in binary mode. 

   Example:  A bitmask of 10000000000000000000000111(0x7h)
The bitmask above hides local drives A, B, and C (rightmost bits from right to left) and drive Z (leftmost bit).

A bit mask of 11111111111111111111111111 (0x3FFFFFFh) would hide all drive letters.

Administrators may also use the NODRIVES entry to disable access to floppy drives on a per-user basis, replacing functionality previously found in the Floplock.exe utility from the Windows NT 3.x resource kits.

Drives hidden using the NODRIVES setting are not available through Windows NT Explorer, under the My Computer icon, or in the File Open\Save dialog boxes of Windows applications. File Manager and the Windows NT command prompt are not affected by this registry setting.

NOTE: If you hide the System drive it is not available under the My Computer icon or in the File Open\Save dialog boxes, however it is visible in Windows NT Explorer.

Additional query words: 4.00 prodnt floplock.exe
Keywords : kbui ntsecurity NTSrvWkst ntui
Version : 4.0
Platform : WinNT
Issue type : kbhowto

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Last reviewed: May 30, 1997
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