This situation usually occurs when a high number of client sessions (RDP or ICA) are connected and actively using the Terminal Server. This situation is more likely to occur if every user has a drive mapped to a common server. Under certain circumstances, this can cause the Terminal Server to stop responding on all client sessions. When this occurs, console response is normal until attempting to use the redirector. CPU usage will normally be very low.
You may experience the following error messages on the Terminal Server computer:
- Event ID: 5719
Description: No Windows NT Domain Controller is available for domain domain_name. The following error occurred:
There are currently no logon servers available to service the logon request.
- Error 1722: The RPC server is unavailable.
- Error 1723: The RPC server is too busy to complete this operation.
- Error 1721: Not enough resources are available to complete this operation.
During negotiation of the SMB dialect, this value is passed to the client's redirector where the limit on outstanding requests is enforced.
When multiple RDP clients are connected to the Terminal Server, there is normally one instance of the Windows shell, Explorer.exe, running for each client.
Explorer makes extensive use of directory notifications, resulting in a number of NTNotifyDirectoryChange SMBs being posted to the server. Directory notifications allow the server to notify the client when file or directory information changes. The NTNotifyDirectoryChange SMB is classified as a long term request. The SMB is received by the server but is not returned until a change occurs (or until the SMB is cancelled by the client).
When several RDP clients connect to the Terminal Server, the number of outstanding commands against the server can exceed the default maximum of 50. If this situation arises, other SMB requests will wait in the redirector until previous requests complete, timeout, or are cancelled.
NOTE: For Windows NT 4.0 Service Pack 3 and later, the valid values for this entry range from 1 to 65535 requests, with a default value of 50 requests. For Windows 2000, the maximum value for this entry is limited to 125 requests to assure that Windows 95 and Windows 98 clients can connect to the server.
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.
WARNING: Making a change to the MaxMpxCt registry entry may cause Windows 95/98 clients to not be able to connect to the server.
- Use Registry Editor to locate the following registry key:HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanServer \Parameters
- Make the following changes:MaxMpxCt REG_DWORD
Range: 1 to 65535 requests
Article ID: 191370 - Last Review: Oct 31, 2006 - Revision: 1