Disable MAPI clients warning

[This topic is intended to address a specific issue called out by the Exchange Server Analyzer Tool. You should apply it only to systems that have had the Exchange Server Analyzer Tool run against them and are experiencing that specific issue. The Exchange Server Analyzer Tool, available as a free download, remotely collects configuration data from each server in the topology and automatically analyzes the data. The resulting report details important configuration issues, potential problems, and nondefault product settings. By following these recommendations, you can achieve better performance, scalability, reliability, and uptime. For more information about the tool or to download the latest versions, see "Microsoft Exchange Analyzers" at https://go.microsoft.com/fwlink/?linkid=34707.]  

Topic Last Modified: 2010-04-01

The Microsoft Exchange Best Practices Analyzer reads the following registry entry to determine whether MAPI client blocking has been set:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeIS\ParametersSystem\Disable MAPI Clients

If the Exchange Best Practices Analyzer finds that the value for Disabled MAPI Clients is set with a value that blocks all MAPI clients in the ranges of 6 through 8, the Exchange Best Practices Analyzer displays a warning.

By default, the Disable MAPI Clients key is not enabled. By enabling this key an administrator can block specific versions of Microsoft Office Outlook from connecting to a computer that is running Exchange 2000 Server, Exchange Server 2003, or Exchange Server 2007. For more information about the values that can be set for the Disable MAPI Clients key to block specific versions of Office Outlook from connecting to Exchange Server, All versions of Outlook are allowed to access the server.

Blocking the Exchange System Attendant service will likely cause Exchange Server to malfunction.

To fix this warning, follow the recommendations and procedure in All versions of Outlook are allowed to access the server.

For more information about blocking specific MAPI clients from connecting to a computer that is running Exchange 2000 Server or Exchange Server 2003, see the following Microsoft Knowledge Base articles:

For more information about how to block specific MAPI clients from connecting to a computer that is running Exchange Server 2007, see the Exchange Management Shell Set-CasMailbox cmdlet.

For more information about blocking specific MAPI clients from connecting to a computer that is running Exchange Server 2010, see the Exchange Management Shell Set-rpcclientaccess cmdlet.

For more information about how to download security updates for older versions of Outlook and blocking other versions of Outlook, see Slowing and Stopping E-Mail Viruses in an Exchange Environment.