With Unencrypted Password SP3 Fails to Connect to SMB Server

• Microsoft Windows NT Workstation version 4.0
• Microsoft Windows NT Server version 4.0

SYMPTOMS

After upgrading your Windows NT 4.0 computer to Service Pack 3 (SP3), you are unable to connect to Server Message Block (SMB) servers (such as Samba or Hewlett-Packard (HP) LM/X or LAN Manager for UNIX) with an unencrypted (plain text) password.

When attempting to connect after you upgrade to Windows NT 4.0 Service Pack 3, you receive the following error message:

   System error 1240 has occurred.

   The account is not authorized to login from this station.

CAUSE

This is because the SMB redirector in Service Pack 3 handles unencrypted passwords differently than previous versions of Windows NT. Beginning with Service Pack 3, the SMB redirector does not send an unencrypted password unless you add a registry entry to enable unencrypted passwords.

RESOLUTION

To enable unencrypted (plain text) passwords, modify the registry in the following way:

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

1. Run Registry Editor (Regedt32.exe).

2. From the HKEY_LOCAL_MACHINE subtree, go to the following key:

   \system\currentcontrolset\services\rdr\parameters

3. Click Add Value on the Edit menu.

4. Add the following:

         Value Name: EnablePlainTextPassword
         Data Type: REG_DWORD
         Data: 1
   

5. Click OK and then quit Registry Editor.

6. Shut down and restart Windows NT.

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

Add the following line to the Product.Add.Reg section of the Update.inf file:

   HKLM,System\CurrentControlSet\Services\Rdr\Parameters,
   "EnablePlainTextPassword", 0x10001, 1