Yes, PR_CONVERSATION_INDEX is lost on external e-mails. You coudl in theory extract In-Reply-To headers from the extrenal messages, but that does not work too well... I used ConversationIndex and I was able to get it to work for the most part, but it seems like some external e-mails have the Conversation Index reset. I'm going to assume from your inquiry that POP3/SMTP reset the index. Is there anyway to handle these? Here is my code: Public Sub LeafCollector() Dim lConIndex As String Dim lMailItem As Long Dim lMailItem2 As Long Dim bDontSave As Boolean Dim myOutlook As Outlook.Application Dim myNameSpace As Outlook.NameSpace Dim oItems2 As Outlook.Items Set myOutlook = Outlook.Application Set myNameSpace = myOutlook.GetNamespace("MAPI") If myOutlook.ActiveExplorer.CurrentFolder.DefaultMessageClass <> "IPM.Note" Then MsgBox "This macro can only be run on e-mail folders." Else Select Case UCase(myOutlook.ActiveExplorer.CurrentFolder.Name) Case "INBOX CHRON", "SENT ITEMS" 'Do not allow it to be run on these folders MsgBox "Running this on Inbox Chron or Sent Items will tie up this machine for a long time. Outlook cannot be used while this is running. If you need to run this on this folder, please contact Rick Bray to make a qhick code change to allow this." Set myNameSpace = Nothing Set myOutlook = Nothing Exit Sub Case Else If MsgBox("There are " & myOutlook.ActiveExplorer.CurrentFolder.Items.Count & " items in this folder. Are you sure you want to run this on '" & myOutlook.ActiveExplorer.CurrentFolder.Name & "' ?", vbExclamation + vbYesNo, "Non-Sanctioned Outlook Folder") = vbNo Then Set myNameSpace = Nothing Set myOutlook = Nothing Exit Sub Else Set oItems2 = myOutlook.ActiveExplorer.CurrentFolder.Items End If End Select End If If Outlook.ActiveExplorer.Selection.Count > 0 Then For lMailItem = 1 To myOutlook.ActiveExplorer.CurrentFolder.Items.Count 'Loop through every e-mail Set myMailItem = myOutlook.ActiveExplorer.CurrentFolder.Items (lMailItem) bDontSave = False lConIndex = myMailItem.ConversationIndex For lMailItem2 = 1 To oItems2.Count 'Compare e-mail against every other e-mail until match is found If lMailItem <> lMailItem2 Then If oItems2(lMailItem2).ConversationIndex <> lConIndex Then If Left(oItems2(lMailItem2).ConversationIndex, Len(lConIndex)) = lConIndex Then bDontSave = True Exit For End If End If End If Next If myMailItem.UserProperties("SAVE") Is Nothing Then myMailItem.UserProperties.Add "SAVE", olText, True End If If bDontSave = False Then 'Label as KEEP so it is not removed. myMailItem.UserProperties("SAVE") = "KEEP" Else 'Label with folder name, so we can replace if it was removed in error. myMailItem.UserProperties("SAVE") = myOutlook.ActiveExplorer.CurrentFolder.Name End If myMailItem.Save Next For lMailItem2 = oItems2.Count To 1 Step -1 'Delete any e-mail that is not labeled as KEEP If oItems2(lMailItem2).UserProperties("SAVE") <> "KEEP" Then oItems2(lMailItem2).Delete End If Next lMailItem2 End If End Sub On Nov 22, 1:08 pm, "Dmitry Streblechenko" <dmi...@dimastr.com> wrote: