Hi @mively
Can you try this
sum_Vencidos = DT.AsEnumerable().
Where(Function(row) Not String.IsNullOrWhiteSpace(row("Vencidos").ToString())).
Sum(Function(row) Convert.ToDouble(row("Vencidos").ToString().Replace(".","").Replace(",", ".")))
Use Write Cell activity and give below
DT.Rows.Count+1
Regards,