Nwrdr.sys Fails Reading File with Execute Only Attribute

• Microsoft Windows NT operating system version 3.1
• Microsoft Windows NT Advanced Server version 3.1
• Microsoft Windows NT Workstation versions 3.5, 3.51, and 4.0
• Microsoft Windows NT Server versions 3.5, 3.51, and 4.0

SYMPTOMS

If a NetWare administrator changes the file attributes of executable files to Execute Only, the following error message appears on any Windows NT computer accessing the files through either Client Services for NetWare or Gateway Services for NetWare:

   The system cannot find the file <drive>:\<directory>\<executable file>

CAUSE

Windows NT does not recognize the Execute Only file attribute.

WORKAROUND

To work around this problem:

1. Rename or remove the executable file.

2. Reinstall the file or restore the file from a previous backup.

   ... once assigned, this attribute cannot be removed.

STATUS

Microsoft has confirmed this to be a problem in Windows NT versions 3.1, 3.5, 3.51, and 4.0. This problem was corrected in the latest Microsoft Windows NT 4.0 U.S. Service Pack. For information on obtaining the service pack, query on the following word in the Microsoft Knowledge Base (without the spaces):

   S E R V P A C K

MORE INFORMATION

The default behavior explained above can be altered to allow Nwrdr.sys to read Execute Only files. The fix and a new registry parameter are required. The following instructions explain how to enable this functionality:

WARNING: Using the 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. Rename the existing Nwrdr.sys file in the %Systemroot%\System32\Drivers directory.

2. Copy the new Nwrdr.sys file to the same location.

3. Add the following registry values by running Regedt32.exe.

   In HKEY_LOCAL_MACHINE on Local Machine:

      Key Name:        SYSTEM\CurrentControlSet\Services\NwRdr\Parameters
      Name:            ReadExecOnlyFiles
      Type:            REG_DWORD
      Data:            0x1
   
   

4. Stop and restart Client Services for NetWare or Gateway Services for NetWare, depending on whether the fix is applied to Windows NT Workstation or Windows NT Server.