Broadcast a Shutdown Message (Command Prompt)
Applies to: 
SQL Server
This topic describes how to broadcast a shutdown message in SQL Server by using the net send command. In the message, include the time the instance of SQL Server will be stopped so that users can finish their tasks.
To broadcast a shutdown message
From a command prompt, enter:
net send /users "message"
The /users option specifies that the message be sent to all users connected to the server
Note
The net send command requires the messenger service to be running on both the sending and the receiving computers. The messenger service is disabled by default on Windows Server 2003. For information about net send, see the Windows documentation.
On your network, it may be more appropriate to contact users by e-mail or the telephone. To determine which users are currently connected to SQL Server, use the Activity Monitor. For information on the Activity Monitor, see Activity Monitor and Open Activity Monitor (SQL Server Management Studio).