I say "bug" as i think this may be a issue with me not with zimbra...

As outlook does not have anyway to train the spam filter, and i do not know vbs well enough, i googled a way to create a button that forwards the email, and either a) deletes it or b) moves it to the junk folder.
As only one user wants the email in the junk folder and the bug happens to everyone it must be something in the forward/delete code that causes outlook to crash on exit.
If this is used outlook will crash every time a few seconds after closing.
If it is not used outlook does not crash

Sub ForwardItem()
    Dim oExplorer As Outlook.Explorer
    Dim oMail As Outlook.MailItem
    Dim oOldMail As Outlook.MailItem

    Set oExplorer = Application.ActiveExplorer
    If oExplorer.Selection.Item(1).Class = olMail Then
        Set oOldMail = oExplorer.Selection.Item(1)
        Set oMail = oOldMail.Forward
        oMail.DeleteAfterSubmit = True
        oMail.Recipients.Add "spam.bmutmdq5c@mail.tk.on.ca"
        If oMail.Recipients.Item(1).Resolved Then
            MsgBox "Could not resolve " & oMail.Recipients.Item(1).Name
        End If
        MsgBox "Not a mail item"
    End If
End Sub
If someone can either a) point and laugh at a critical error in the code, or b) test the code to confirm it is a bug I would greatly appreciate it