The Outbox property returns a Folder object representing the current user's Outbox folder. Read-only.
objSession.Outbox
Object (Folder)
The Outbox property returns Nothing if the current user does not have or has not enabled the Outbox folder.
In addition to the general ability to navigate through the formal collection and object hierarchy, CDO supports properties that allow your application to directly access the most common Folder objects:
' from the function Session_Outbox
Dim objFolder As Object
'
Set objFolder = objSession.Outbox
If objFolder Is Nothing Then
MsgBox "Failed to open Outbox"
Exit Function
End If
MsgBox "Outbox folder name = " & objFolder.Name
Set objMessages = objFolder.Messages