How to uniquely identify an Outlook email as MailItem.EntryID changes when email is moved

Question

My company uses a single email address for customers to send requests and orders to. we created an Access database that import emails into a table. The table creates it\'s o

Answer 1

Here is VBA code tested in MS Access 2013 to extract the PR_SEARCH_KEY from an Outlook.MailItem and convert to a string:

Public Function strGetMailItemUniqueId( _
    olMailItem As Outlook.MailItem _
) As String
    Dim PR_SEARCH_KEY As String
    PR_SEARCH_KEY = "http://schemas.microsoft.com/mapi/proptag/0x300B0102"

    Dim olPA As Outlook.PropertyAccessor
    Set olPA = olMailItem.PropertyAccessor

    Dim vBinary As Variant
    vBinary = olPA.GetProperty(PR_SEARCH_KEY)

    strGetMailItemUniqueId = olPA.BinaryToString(vBinary)
End Function

Answer 2

In Microsoft Outlook versions like 2007, 2010, Office 365 etc. there is a property Message-ID in the headers section of the email.

You can use this property to uniquely identify an email.

Answer 3

You can use the PR_SEARCH_KEY property (DASL name http://schemas.microsoft.com/mapi/proptag/0x300B0102) - it does not change when a message is moved. It can be accessed through MailItem.PropertyAccessor.GetProperty, but unfortunately you cannot use PT_BINARY properties in Items.Find/Restrict.

You can also set your own named property using MailItem.UserProperties.

UPDATE:

For PR_SEARCH_KEY, see https://msdn.microsoft.com/en-us/library/office/cc815908.aspx.

MaillItem.UserProperties can be used from anywhere - Outlook Object Model is Outlook Object Model whether it is used from inside Outlook or externally from Excel. Keep in mind that setting a user property and daving the item will change its last modified date.

If you want to stick to PR_SEARCH_KEY, to be be able to sort on it, you might want to look at Redemption - its RDOFolder.Items.Find / Restrict methods allow PT_BINARY properties in its queries, e.g. "http://schemas.microsoft.com/mapi/proptag/0x300B0102" = '89F75D48972B384EB2C50266D1541099'