Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool reads the following registry key to determine the value data for the MaxClientRequestBuffer value:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\W3SVC\Parameters\MaxClientRequestBuffer

If the Exchange Server Analyzer finds that the value data for MaxClientRequestBuffer value is lower than 16,384, the Exchange Server Analyzer displays a warning.

If the value for MaxClientRequestBuffer is too low, it could cause errors for Microsoft Office Outlook® Web Access users. Specifically, it could cause HTTP 400 - Bad Request to be returned to the browser. To correct this warning, it is recommended that you either increase the value to a number greater than 16,384 or remove the registry value to revert to the default settings. The MaxClientRequestBuffers value is not present by default.

Important:
This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore the registry if a problem occurs. For information about how to restore the registry, view the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.
To correct this warning by increasing the value for the value data

  1. Open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to: HKLM\System\CurrentControlSet\W3SVC\Parameters\MaxClientRequestBuffer

  3. Double-click the MaxClientRequestBuffer value and edit the value data. Set the value data to a decimal number that is equal to or greater than 16,384.

  4. Close the registry editor and then restart the Exchange server.

To correct this warning by removing the value

  1. Open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to: HKLM\System\CurrentControlSet\W3SVC\Parameters\MaxClientRequestBuffer

  3. Right-click the MaxClientRequestBuffer value, and then click Delete.

  4. Close the registry editor and restart the Exchange server.

Before you edit the registry, and for information about how to edit the registry, see Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows registry" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=256986).

For more information about the MaxClientRequestBuffer registry value, see Microsoft Knowledge Base article 260694, "Description of the MaxClientRequestBuffer Registry Value" (http://go.microsoft.com/fwlink/?linkid=3052&kbid=260694).