Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool reads the following registry key to determine whether the FXGetBuffer Backoff Constant value has been created:

HKEY_LOCAL_MACHINE \SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem

If the Exchange Server Analyzer finds that the FXGetBuffer Backoff Constant value has been created under the ParametersSystem registry key, the Exchange Server Analyzer displays a non-default configuration message.

You can use the FXGetBuffer Backoff Constant value to control the number of Microsoft Office Outlook® 2003 clients that synchronize with an Exchange Server 2003 server at one time. You set the FXGetBuffer Backoff Constant value to configure the amount of time that an Outlook client waits before the Outlook client attempts to synchronize again. The default value of the FXGetBuffer Backoff Constant value is 500 milliseconds.

The Exchange Server Analyzer reports this configuration for informational purposes only. No action is required. However, you can delete the FXGetBuffer Backoff Constant registry key if you want to restore the default configuration.

This article contains information about editing the registry. Before you edit the registry, make sure that you understand how to restore the registry if a problem occurs. For information about how to restore the registry, see the "Restore the Registry" Help topic in Regedit.exe or Regedt32.exe.
To restore the default configuration
  1. Open a registry editor, such as Regedit.exe or Regedt32.exe.

  2. Navigate to: HKLM\SYSTEM\CurrentControlSet\Services\MSExchangeIS\ParametersSystem

  3. Delete the FXGetBuffer Backoff Constant value.

  4. Close the registry editor.

The Microsoft Exchange Information Store service detects the changes in minutes. You do not need to restart the computer.

Before you edit the registry, and for information about how to edit the registry, see the Microsoft Knowledge Base article 256986, "Description of the Microsoft Windows Registry" (

For more information about setting registry keys to control the number of Outlook clients that can synchronize with Exchange Server 2003, see the Knowledge Base article 818484, "Registry Values and Counters That You Can Use to Configure and Monitor Outlook Client Synchronization" (