Excel process not closing [duplicate]

Answer 1

I finally got it to close. You need to add a variable for the Workbooks collection, and then use the FinalReleaseComObject as stated in the other answers. I guess every possible Excel COM object that you use must be disposed this way.

try
        {
           // Create an instance of Microsoft Excel and make it invisible
           excelApp = new Excel.Application();
           excelApp.DisplayAlerts = false;
           excelApp.Visible = false;

           // open a Workbook and get the active Worksheet

           excelWorkbooks = excelApp.Workbooks;
           excelWorkbook = excelWorkbooks.Open(excelFile, Type.Missing, true);
           excelWorkSheet1 = excelWorkbook.ActiveSheet;

        }
        catch
        {
           throw;
        }
        finally
        {

           NAR( excelWorkSheet1 );
           excelWorkbook.Close(false, System.Reflection.Missing.Value, System.Reflection.Missing.Value);
           NAR(excelWorkbook);
           NAR(excelWorkbooks);
           excelApp.Quit();
           NAR(excelApp);

        }
     }
     private void NAR(object o)
     {
        try
        {
           System.Runtime.InteropServices.Marshal.FinalReleaseComObject( o );
        }
        catch { }
        finally
        {
           o = null;
        }
     }