'declare these 2 variables at top of sheet module ABOVE all procedures
Private oldvalue As String, Ref As String
Private Sub Worksheet_Change(ByVal Target As Range)
If Not Intersect(Range("C2:C156"), Target) Is Nothing Then
If Target.Address = Ref Then
Application.EnableEvents = False
If oldvalue <> Target.Value Then Target.Offset(, 17).Value = oldvalue
Application.EnableEvents = True
End If
oldvalue = ""
Ref = ""
End If
End Sub
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
If Selection.Count <> 1 Then Exit Sub
If Not Intersect(Range("C2:C156"), Target) Is Nothing Then
oldvalue = Target.Value
Ref = Target.Address
End If
End Sub