Windows NT 4.0 Fails to Shutdown Completely

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

SYMPTOMS

When performing a routine system shutdown, Windows NT waits indefinitely while the message "writing unsaved data to disk" is displayed. The system fails to completely shutdown.

In this particular case, analysis of network traffic in and out of a computer in this state will show that the redirector is still active, but that the server service is not responding to requests.

If a network sniff is not practical, but TCP/IP is in use, the system will still be found to be responding to ping requests.

CAUSE

If a particular set of network traffic is directed at a system during a small window of time while the server service is going through its own shutdown code, the server service can fail to close out all client connections and will wait indefinitely, thus blocking the rest of the system from shutting down in an orderly manner.

The window of vulnerability is normally very short, but is variable and depends on the nature of other applications and services that might have been running on the system just prior to shutdown.

Note, too, that there are other reasons why a Windows NT system might fail to shut down besides the one described here.

WORKAROUND

Systems which experience this problem may be successfully shut down by using the Shutdown.exe program with the "/c" switch. However, this is not a recommended solution, as it does not give applications and services the opportunity to do an orderly shutdown.

Another workaround in some cases is to first stop any applications or services that might have been identified as aggravating the problem, then waiting several minutes before initiating a system shutdown.

Yet another option, because the problem is brought on when network clients attempt to connect to the system during shutdown, is to take measures to avoid client activity directed at a vulnerable server when the server needs to be shut down.

Alternatively, obtain the hotfix mentioned below.

STATUS

Microsoft has confirmed this to be a problem in Windows NT version 4.0. A supported fix is now available, but has not been fully regression tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.