Topic Last Modified: 2005-11-18

The Microsoft® Exchange Server Analyzer Tool reads the following registry entry to determine whether the Max FXGetBuffer Users registry key has been created:


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

You can use the Max FXGetBuffer Users registry key to control the number of Microsoft Office Outlook® 2003 clients that synchronize with an Exchange Server 2003 server at the same time. You set the value for the Max FXGetBuffer Users registry key to override the limit on simultaneous remote procedure call (RPC) connections that are made by Outlook clients. These connections are sometimes referred to as ropFXSrcGetBuffers. You calculate the default value for the Max FXGetBuffer Users registry key by taking the number of processors that are on the server, multiplying that number by 2, and then adding 3. For example, on an Exchange Server 2003 server that has two processors, the default value is 7 ([2*2] + 3=7).

The Exchange Server Analyzer reports this configuration for informational purposes only. No action is required.

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 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 Max FXGetBuffer Users value.

  4. Close the registry editor.

The Microsoft Exchange Information Store service detects the changes in minutes. You do not have 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" (