Exception (HRESULT: 0x800AC472) when using Excel.Worksheet.Select after calling Excel.Workbook.SaveAs

Question

I'm opening an xlsx file and saving each sheet into a csv file.

Here is the relevant code for the saving:

int i=0;
foreach (Excel.Worksheet s in app.ActiveWorkbook.Sheets)
{
    s.Select(true); // Error here

    String outfile = outputpath + "("+i+")" + outputfilename + ".csv";
    wkb.SaveAs(outfile, Excel.XlFileFormat.xlCSVMSDOS);

    ++i;
}

There is no problem with the output file name or path, and the output file(s) do not exist. It saves the first two sheets then crashes. I tried with a different input file with 4 sheets and it worked perfectly, so it has to do with the input file.

The exception:

System.Runtime.InteropServices.COMException was unhandled
  HResult=-2146777998
  Message=Exception from HRESULT: 0x800AC472
  Source=ExcelXlsx2Csv
  ErrorCode=-2146777998
  StackTrace:
       at Microsoft.Office.Interop.Excel._Worksheet.Select(Object Replace)
       at ExcelXlsx2Csv.Program.Main(String[] args) in c:\Users\Edward\Documents\Visual Studio 2013\Projects\ExcelXlsx2Csv\ExcelXlsx2Csv\Program.cs:line 109
       at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()
  InnerException: 

Any hints appreciated!

Answer 1

In my case, the exception was been thrown because my excel Interop tools was displaying a modal dialog (associated with a expired licence key - shame on me). If I closed the dialog (which was been displayed in the background) and then hit 'continue' in Visual Studio, the program was able to connect to the xlsx file and retrive data succesfully.