This documentation is archived and is not being maintained.

Installing the MAPI Subsystem

This content is outdated and is no longer being maintained. It is provided as a courtesy for individuals who are still using these technologies. This page may contain URLs that were valid when originally published, but now link to sites or pages that no longer exist.

Supported versions of Windows install the MAPI stub library, Mapi32.dll, in the <drive>\Windows\System32 folder.

The supported versions of Windows are as follows:

Windows Vista

Windows Server 2008

Windows Server 2003

Windows XP

To correctly install the MAPI subsystem, install an application that contains a MAPI-based subsystem, such as Microsoft Office Outlook.

You can find information about a computer's MAPI subsystem installation in the system registry. All values in the registry entries are character strings.

Message service installation programs are responsible for creating the installation information in the following system registry key:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows Messaging Subsystem

Message services must add entries to the system registry.

The following table summarizes how clients retrieve version information for the MAPI subsystem on their computer.

To check


Availability of MAPI

Look for MAPIX=1.

Available version of MAPI

Look for a MAPIXVER string of the form "x.x.x".