MAPI Properties

Description: Contains the sum, in bytes, of the sizes of all properties on a message object.
Property ID: $0E08
Property type: PT_LONG
Area: General messaging

It is recommended that message objects expose this property. The message size indicates the approximate number of bytes that are transferred when the message is moved from one message store to another. Being the sum of the sizes of all properties on the message object, it is usually considerably greater than the message text alone.
Most message store providers compute this property for messages that they handle. However, some message store providers do not support this property. In any case, this property is not available until the IMAPIProp::SaveChanges or Imessage::SubmitMessage method has been called.