MIME type and subtype for an attachments are not associated correctly

When creating a MIME message with attachment in Notes client, a MIME type/subtype of application/octet-stream will be applied

This has been identified as a product defect under APAR LO45329 / SPR # HTAA5T8589

The client will first check the operating system to determine what file associations are defined. Clients running on Microsoft Windows check the Windows registry, while clients running on the Macintosh check Internet Config. If the client cannot locate MIME type information from these sources, it should then check the Domino Directory for a File
Identification document that applies to files with the same extension as the attached file. In fact, the client does not check the Domino Directory, but instead checks the local names.nsf

The problem can be resolved in two ways -
1. Modify the o/s tables
2. Copy the "($FileIdentifications)" view and the needed File Identifications documents from the Domino Directory to the local names.nsf. There may not be a document for the filetype you require and you may have to modify the o/s tables in any case.

The Windows registry key where type/subtype entries are stored is
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\InetInfo\Parameters\MimeMap
This key is not predefined by Microsoft and needs to be created. Create entries in this key of type string with the following syntax:
type/subtype,filetype,,5
Example - application/pdf,pdf,,5
The string does not need a Data value.

On Mac OSX, there is no direct interface to change settings. The Launch Services API is used for this. One freeware product that allows you to modify this info via System Preferences is RCDefaultApp, available here: http://www.rubicode.com/Software/RCDefaultApp/