Conversion from XLSB to XLSX using microsoft interop

if (!File.Exists(strPath + filename.ToUpper().Replace("XLSB", "xlsx")))
                                {

                                    try
                                    {
                                        Application excelApplication = new Application();
                                        Workbooks workbooks = excelApplication.Workbooks;
                                        // open book in any format
                                        Workbook workbook = workbooks.Open(strPath + filename, XlUpdateLinks.xlUpdateLinksNever, true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

                                        // save in XlFileFormat.xlExcel12 format which is XLSB
                                        workbook.SaveAs(strPath + filename.Substring(0, filename.Length - 4) + "xlsx", XlFileFormat.xlOpenXMLWorkbook, Type.Missing, Type.Missing, Type.Missing, Type.Missing, XlSaveAsAccessMode.xlNoChange, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

                                        // close workbook
                                        workbook.Close(false, Type.Missing, Type.Missing);

                                        // ...
                                        System.Runtime.InteropServices.Marshal.ReleaseComObject(workbook);
                                        System.Runtime.InteropServices.Marshal.ReleaseComObject(workbooks);
                                        System.Runtime.InteropServices.Marshal.ReleaseComObject(excelApplication);
                                        // shutdown excel
                                        //excelApplication.Quit();
                                    }
                                    catch (Exception ex)
                                    {
                                        ClientSumDesc = "Load Failed, XLSB File Conversion" + ex;
                                        return true;
                                    }
                                    finally
                                    {

                                        foreach (System.Diagnostics.Process proc in System.Diagnostics.Process.GetProcessesByName("EXCEL"))
                                        {
                                            proc.Kill();
                                        }
                                    }
                                }