DOCUMENT:Q168600  31-JUL-2001  [sms]
TITLE   :SMS: Simultaneous Attempts to Remote Control May Cause Errors
PRODUCT :Microsoft Systems Management Server
PROD/VER:winnt:1.2
OPER/SYS:
KEYWORDS:kbnetwork kbtshoot smsremtshoot kbRemoteProg

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The information in this article applies to:

 - Microsoft Systems Management Server version 1.2 
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SYMPTOMS
========

Windows NT Server Remote Control (Wuser32.exe) may fail if multiple Systems
Management Server administrators attempt to take control at the same time. When
Remote Control fails, the "Quick Windows Viewer" on the controlling computer
running Systems Management Server will appear to stop responding, and
Wuser32.exe may cause an error to occur on the client computer running Windows
NT Workstation.

   WUSER32.exe Application Error:

   The Instruction at "0x77a835e1" referenced memory at "0x21270028". The memory
   could not be "read".
   Click on OK to terminate the application.
   Click on CANCEL to debug the application.

Nobody will be able to take remote control of that computer until either it is
shut down and restarted, or the Systems Management Server Remote Control Agent
Service is restarted.

CAUSE
=====

Windows NT Server Remote Control allows only one computer running Systems
Management Server to control the client at a time. If multiple computers running
Systems Management Server attempt to control the client, Wuser32.exe initially
accepts the connections, starts to verify permissions, and then disconnects the
additional Systems Management Server connections because it is already being
controlled.

When a Systems Management Server connection is disconnected, Wuser32.exe parses
through a list of security contexts held for Systems Management Server
connections. If a security context has been inactive in the list for more than
one minute, Wuser32.exe frees the context.

When the Systems Management Server administrator that currently has control of
the workstation attempts to perform a remote task in the "Quick Windows Viewer",
Wuser32.exe on the client computer running Windows NT Workstation looks up the
security context for that Systems Management Server connection to verify
permissions. If the Systems Management Server administrator's security context
was freed during the connection termination of another computer running Systems
Management Server, Wuser32.exe passes an invalid security context to Windows NT
Server. The invalid security context causes Wuser32.exe to cause an access
violation (AV) and the "Quick Windows Viewer" will appear to stop responding.

RESOLUTION
==========

To resolve this problem, obtain the hotfix mentioned below. With the hotfix,
Wuser32.exe was modified to clean up inactive security contexts without
releasing the active Systems Management Server administrator's security context.

STATUS
======

Microsoft has confirmed this to be a problem in Systems Management Server
version 1.2. This problem has been corrected in the latest U.S. Service Pack for
Systems Management Server version 1.2. 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

Additional query words: prodsms DrWatson GPF

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Keywords          : kbnetwork kbtshoot smsremtshoot kbRemoteProg 
Technology        : kbSMSSearch kbSMS120
Version           : winnt:1.2
Issue type        : kbbug
Solution Type     : kbfix

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