CanonicalName: PidTagEntryId
PropertyID: $0FFF
Area: ID properties
Description: Contains a MAPI entry identifier used to open and edit properties of a
particular MAPI object.
Remarks: This property identifies an object for OpenEntry to instantiate and
provides access to all of its properties through the appropriate derived
interface of IMAPIProp.

This property is one of the base address properties for all messaging

This property can contain either a long-term or a short-term identifier.
Short-term identifiers are easier and faster to construct, but are limited
in their scope and duration, typically to the current session and
workstation. They are commonly used for objects of a temporary nature, such
as table rows or dialog box entries, and then abandoned. Long-term
identifiers are used for objects of a more wide-ranging and long-lasting

This property is always available through the IMAPIProp::GetProps method
following the first call to the IMAPIProp::SaveChanges method. Some service
providers can make it available immediately after instantiation. The
provider must always return a long-term entry identifier from GetProps.
Therefore, to convert a short-term identifier to long-term, simply open the
object and get its this property through GetProps.