ExitWindowsEx Does Not Work With NEC Power Switch Service

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

SYMPTOMS

NEC has a power switch service that calls ExitWindowsEx to shut down and power off computers. This service worked both before and after logging on to Windows NT 3.51, but fails before logging on to Windows NT 4.0

                                        NT4.0    NT 3.51
After Logon:                            WORKS    WORKS
After Logon when workstation is locked: FAILS    WORKS
Before Logon:                           FAILS    WORKS

1. Log on to the system.

2. Press Ctrl+Alt+Del.

3. Click Lock Workstation.

4. Press Ctrl+Alt+Del (to get the lock dialog box).

5. Press the power switch.

   This causes a power switch interrupt. The NEC power switch driver catches the interrupt and calls the power switch service. NEC power switch service calls ExitWindowsEx.

6. The machine does not shut down. The system is generally unusable.

CAUSE

The lock workstation routine does not process the WLX_SAS,WLX_SAS_TYPE_USER_LOGOFF message.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Windows NT version 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