Microsoft states in their article: 258021

Event ID 52 When You Start Terminal Services
View products that this article applies to.
Article ID : 258021
Last Review : May 4, 2006
Revision : 4.0
This article was previously published under Q258021
IMPORTANT: This article contains information about modifying the registry. Before you modify the registry, make sure to back it up and make sure that you understand how to restore the registry if a problem occurs. For information about how to back up, restore, and edit the registry, click the following article number to view the article in the Microsoft Knowledge Base:
256986 (http://support.microsoft.com/kb/256986/EN-US/) Description of the Microsoft Windows Registry
SYMPTOMS
Clients cannot connect to a Windows 2000-based server that is running Terminal Services, even after you reset the client license registry key as described in following Microsoft Knowledge Base article:
248430 (http://support.microsoft.com/kb/248430/EN-US/) How to Transfer Terminal Services CAL from One Computer to Another
The client computer may receive the following error messages if you try to establish a Terminal Services connection:
Terminal Services Client Disconnected

The client could not connect to the Terminal server. The server may be too busy. Please try connecting later.
-or-
Terminal Services Client Disconnected

The Terminal server has ended the connection.
The following event ID message may be logged in the System event log on the server:
Event ID: 52
Description: Object Name not found.
Source: TermService

Data:
=====
0000: 52 00 44 00 50 00 2d 00 R.D.P.-.
0008: 54 00 63 00 70 00 00 00 T.c.p...
0010: 00 00 00 00 00 00 00 00 ........
0018: 00 00 00 00 00 00 00 00 ........
0020: 00 00 00 00 00 00 00 00 ........
0028: 00 00 00 00 00 00 00 00 ........
0030: 00 00 00 00 00 00 00 00 ........
0038: 00 00 00 00 00 00 00 00 ........
0040: 00 00 ..

CAUSE
This problem may occur if the RDP-tcp listener was not initialized or if the Terminal device driver is not started. You may have to verify that the license key is correct.
RESOLUTION
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To resolve this problem, first determine the cause of the problem by using the following list, and then follow the applicable steps:
• The RDP-tcp connection may have to be reset. To reset the RDP-tcp connection in the Terminal Services Configuration management console, right-click the connection, and then click Disable. Confirm the changes when you are prompted to do so. Repeat the process, and then click Enable.
• The RDP-tcp connection may be corrupted. Re-create the RDP-tcp connection in the Terminal Services Configuration management console. To re-create the connection, delete the connection, and then re-create it.
• An evaluation license may have been used to configure Terminal Services Licensing. Verify that a retail license has been issued and correctly installed.
• The Network Adapter tab in RDP-tcp properties may be set to Maximum Connections: 0. This causes the "The Terminal server has ended the connection" error message.
• The Terminal device driver files may be corrupted or missing. Verify the existence of the Termdd.sys and Rdpwd.sys files in the %SystemRoot%\Sytem32\Drivers folder. Verify that the Rdpdd.dll and Rdpwsx.dll files are located in the %SystemRoot%\Sytem32 folder.
• The TermDD service may be disabled. Open the registry and locate the following key:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\TermDD
Check the data setting for the Start value, which should be 2. If the value is set to 4, the driver has been disabled. Set the value to 2, and then restart the server computer.
After you complete these steps, the client license registry may still have to be reset. For additional information about how to reset the client license registry, click the article number below to view the article in the Microsoft Knowledge Base:
248430 (http://support.microsoft.com/kb/248430/EN-US/) How to Transfer Terminal Services CAL from One Computer to Another
You may have to verify the license key by using the Microsoft Registration Authority and Clearinghouse. See the "More Information" section in this article for information about how to contact the Microsoft Registration Authority and Clearinghouse.
STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.
MORE INFORMATION
For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:
237811 (http://support.microsoft.com/kb/237811/EN-US/) How to Activate a Terminal Services License Server and Install CALs Over the Internet
244749 (http://support.microsoft.com/kb/244749/EN-US/) Licenses Required When Using Terminal Services Client Software
258045 (http://support.microsoft.com/kb/258045/EN-US/) Terminal Services Licensing Does Not Accept a Valid License Key Pack
For more information about Terminal Services Licensing, see the technical white paper at the following Microsoft Web site:
Microsoft Windows 2000 Terminal Services Licensing (http://www.microsoft.com/windows2000/techinfo/howitworks/terminal/tslice...)
For more information about Terminal Services, see Chapter 16, "Deploying Terminal Services," in the "Deployment Planning Guide" on the following Microsoft Web site:
http://www.microsoft.com/resources/documentation/windows/2000/server/res... (http://www.microsoft.com/resources/documentation/windows/2000/server/res...)
To validate a Terminal Services License Key in the United States, call 1-888-571-2048 to contact the Microsoft Registration Authority and Clearinghouse.

To contact the Registration Authority and Clearinghouse outside the United States, follow these steps:
1. Start the Terminal Services Licensing tool.
2. Right-click your license server, and then click Properties.
3. Click Connection Method, and then click Set To Telephone.
4. Click the appropriate country, and then click OK.
5. On the Action menu, click Install Licenses, and then click Next.
6. Call the appropriate Customer Service Center by using the telephone number that is displayed.
7. Click Cancel to quit the Terminal Services Licensing tool.
APPLIES TO
• Microsoft Windows 2000 Server
• Microsoft Windows 2000 Advanced Server
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Keywords:
kbprb kbtermserv KB258021