Probably: 
Private Sub Worksheet_Change(ByVal Target As Range)
    Dim Rng As Range
    
    Application.EnableEvents = False
    
    If Target.Column = 4 Then
        If Target.Row > 1 Then
            Target.Offset(, 1).Resize(, 11).ClearContents
        End If
    End If
    
    Set Rng = Intersect(Target, Range("E2:O10000"))
    
    If Not Rng Is Nothing Then
        If HasValidation(Rng) Then
            GoTo EndProc
        Else
            Application.Undo
            MsgBox "Your last operation was cancelled. It would have deleted data validation rules.", vbExclamation
        End If
    End If
    
EndProc:
    Application.EnableEvents = True
End Sub
Artik