Terminal Server Client Connections and Logon Limited by MaxWorkItem and MaxMpxCt Values (232476)

RESOLUTION

To resolve this issue, you must either edit the existing values or add the following registry entries for both MaxWorkItems and MaxMpxCt to the servers from which the clients are requesting resources. By default, MaxWorkItems and MaxMpxCt do not appear under the parameters key although they are in effect.

MaxMpxCt permits a server to provide a suggested maximum number of simultaneous client requests to itself, and then enforces those limits. Because each client connection generates multiple instances (for example, Windows shell and Explorer.exe), with multiple clients connecting to the server, they can be greater than the default MaxMpxCt setting of 50. As soon as this limit is reached for that server, additional requests are refused until it drops below the set limit again.

Note: These values must be added with such a ratio that the value for MaxWorkItems is at least four times as large as that for MaxMpxCt. For example, if MaxMpxCt has a value of 1024, then MaxWorkItems needs to have a value of at least 4096.

Windows NT

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.

1. Start Registry Editor.
2. Locate the following key in the registry:

   HKEY_LOCAL__MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters

3. Double-click the MaxWorkItems value, type 4096, click Decimal, and then click OK.
   
   The number value you enter is arbitrary, and you can also enter 8192, 16384, or 32768 if you want to. However, Microsoft recommends that you start at the lower levels and work up as needed, doubling the value each time. The range for this value is one through 65535. If this value already exists, but you are experiencing problems similar to those outlined earlier, then edit this entry and double its current value but select a minimum value of 4096. For example, if it shows a value of 2048, then change it to 4096. If the problems persist, then continue this process until the issue subsides.
   
   Note: This value must be at least four times as large as the MaxMpxCt value.
4. If the MaxWorkItems value does not exist in the Parameters key, on the Edit menu, click Add Value, and then add the following registry value:

   Value Name: MaxWorkItems
   Data Type: REG_DWORD
   Value: 4096

5. Double-click the MaxMpxCt value, type 1024, click Decimal, and then click OK.
   
   The default value for MaxMpxCt is 50, but remember that MaxWorkItems must be set at least four times as high as the number used for MaxMpxCt.
   
   Note: Windows 95 and Windows 98 clients can interpret this registry entry differently than Windows NT, so apply this value according to which client is being used. For additional information about how Windows 95 and Windows 98 interpret the registry entry differently than Windows NT, click the article number below to view the article in the Microsoft Knowledge Base:

   232890 Windows 98 Client Unable to Connect to Windows NT Share

6. If the MaxMpxCt value does not exist in the Parameters key, on the Edit menu, click Add Value, and then add the following registry value:

   Value Name: MaxMpxCt
   Data Type: REG_DWORD
   Value: 1024 (Decimal)

   Important: When you add this value to the registry of a computer running Windows 95, Windows 98, and Windows 98 Second Edition, set this value to 510 Decimal (or 1fe Hexadecimal). If Windows 95, Windows 98, and Windows NT clients are present, then the value for MaxMpxCt must be set to the default used for Windows95 and Windows 98, because Windows NT reads the value without problems.
7. Quit Registry Editor and restart the computer.

Windows 2000

Note: You may experience a slow network response, and slow file copy performance when many people are using the Terminal server.

On a computer that is running Windows 2000 SP2 or later, follow these steps:

1. Start Registry Editor.
2. Locate, and then click the MaxCmds value under the following key in the registry:

   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\LanmanWorkstation \Parameters

3. On the Edit menu, click DWORD, type 500, and then click OK.
4. Quit Registry Editor.
5. On the remote server, start Registry Editor.
6. Locate, and then click the following key in the registry:

   HKEY_LOCAL__MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters

7. On the Edit menu, click Add Value, and then add the following registry values:

   Value name: MaxWorkItems
   Data type: REG_DWORD
   Radix: Decimal
   Value data: 8192
   
   -and-
   
   Value name: MaxMpxCt
   Data type: REG_DWORD
   Radix: Decimal
   Value data: 500

   Note: You may have to increase these values if the registry key does not work.
8. Quit Registry Editor.
9. Restart both servers.

For additional information about clients being unable to connect, click the article number below to view the article in the Microsoft Knowledge Base: For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base: