Sub Macro2()
Dim aRng As Range
    Set aRng = ActiveDocument.Range
    With aRng.Find
        .ClearFormatting
        .Text = "Section"
        .MatchWildcards = True
        Do While .Execute
            aRng.End = aRng.End + 1
            aRng.Collapse 0
            aRng.MoveEndWhile "0123456789."
            If aRng.Fields.Count > 0 Then
                If aRng.Fields(1).Type = 3 Then aRng.Font.ColorIndex = wdBlue
            Else
                If Len(aRng) > 0 Then
                    aRng.Font.ColorIndex = wdRed
                    ActiveDocument.Comments.Add _
                            Range:=aRng, _
                            Text:="Missing cross-reference field code"
                End If
            End If
            aRng.Collapse 0
        Loop
    End With
    MsgBox "Done!", vbInformation
    Set aRng = Nothing
End Sub