Dim dRng As Range, lRow As Long
[U]lRow = Cells(Rows.Count, "J").End(xlUp).Row[/U]
On Error Resume Next
Set dRng = Range("D1:D" & lRow).SpecialCells(xlBlanks)
On Error GoTo 0
If dRng Is Nothing Then
MsgBox "Pls ensure Col D is not empty", vbExclamation
Exit Sub
End If