MAPI creates a tree of folders beneath the root folder of a message store for all clients that send messages to and receive messages from human rather than machine recipients. Messages exchanged between human recipients are known as interpersonal messages and this tree is known as the interpersonal message, or IPM, subtree. The IPM subtree consists of the following folders:
These are the default names and roles for each of these folders; a client can specify its own names if the default names are not appropriate. MAPI assigns default names and associations for these folders to keep messages from inadvertently disappearing if a client neglects to establish receive folders for messages.
The Inbox typically holds incoming messages and the Outbox holds outgoing, or "to be sent", messages. The Sent Items folder holds a copy of each sent message if the client has set the PR_SENTMAIL_ENTRYID property to the entry identifier of this folder. The Deleted Items folder contains messages marked for removal.