With this method: Dim f As Aspose.Cells.FileFormatInfo = Aspose.Cells.FileFormatUtil.DetectFileFormat("really_old.xls") I am able to detect f.FileFormatType = FileFormatType.Excel95 I realize your product inf…...Cells could open/process the file fine, there...alternative I am afraid: e.g Open your template file into MS Excel...