Installing the MAPI Subsystem
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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:
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.
Availability of MAPI
Look for MAPIX=1.
Available version of MAPI
Look for a MAPIXVER string of the form "x.x.x".