Exception from HRESULT: 0x800A03EC Error

I am getting "HRESULT: 0x800A03EC" error when running Excel add-in with following code:

Excel.Range rng = ActiveSheet.Cells[x, y] as Excel.Range;                
string before = rng.Value2; 
string cleanV = System.Text.RegularExpressions.Regex.Replace(before, @"\s+", "");
rng.set_Value(cleanV);

When error happens X and Y are set to 1, thus Excel range is not violated. I searched extensively and tried a number of ways of setting the cell value (eg. Cells[x,y], range.set_Value()) but am at loss why this error happens and how to avoid it.

Any help is greatly appreciated.

Below are exception details:

System.Runtime.InteropServices.COMException was unhandled by user code
  HResult=-2146827284
  Message=Exception from HRESULT: 0x800A03EC
  Source=""
  ErrorCode=-2146827284
  StackTrace:
       at System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)
       at Microsoft.Office.Interop.Excel.Range.set_Value(Object RangeValueDataType, Object value)
       at ImportValidation.ThisAddIn.removeAnySpaces(Int32 x, Int32 y) in c:\Users\dshevelev\Documents\Visual Studio 2012\Projects\ImportValidation\ImportValidation\ThisAddIn.cs:line 354
       at ImportValidation.ThisAddIn.ReadHeaders(Hashtable columnAddress) in c:\Users\dshevelev\Documents\Visual Studio 2012\Projects\ImportValidation\ImportValidation\ThisAddIn.cs:line 123
       at ImportValidation.ThisAddIn.mapColumns() in c:\Users\dshevelev\Documents\Visual Studio 2012\Projects\ImportValidation\ImportValidation\ThisAddIn.cs:line 493
       at ImportValidation.Ribbon1.button6_Click(Object sender, RibbonControlEventArgs e) in c:\Users\dshevelev\Documents\Visual Studio 2012\Projects\ImportValidation\ImportValidation\Ribbon1.cs:line 55
       at Microsoft.Office.Tools.Ribbon.RibbonPropertyStorage.ControlActionRaise(IRibbonControl control)
       at Microsoft.Office.Tools.Ribbon.RibbonPropertyStorage.ButtonClickCallback(RibbonComponentImpl component, Object[] args)
       at Microsoft.Office.Tools.Ribbon.RibbonManagerImpl.Invoke(RibbonComponentCallback callback, Object[] args)
       at Microsoft.Office.Tools.Ribbon.RibbonMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
       at Microsoft.Office.Tools.Ribbon.RibbonManagerImpl.System.Reflection.IReflect.InvokeMember(String name, BindingFlags invokeAttr, Binder binder, Object target, Object[] args, ParameterModifier[] modifiers, CultureInfo culture, String[] namedParameters)
  InnerException: 

Got same error in this line

 Object temp = range.Cells[i][0].Value;

Solved with non-zero based index

 Object temp = range.Cells[i][1].Value;

How is it possible that the guys who created this library thought it was a good idea to use non-zero based indexing?

This is a common but poorly documented Excel COM Error. I've seen it documented as "NAME_NOT_FOUND", meaning that Excel's COM layer is disabled, and can't find the COM property or method name.

I get this error consistently when running the COM code while Excel is 'busy', for example if you set a timer that will start the code, and the code starts running while the user is editing a cell or pressing down their mouse button, then you'll always get this error. This error only happens when the code runs on the main Excel thread, but seems to be the equivalent of error VBA_E_IGNORE = 0x800AC472, which you get when calling the Excel COM object model from another thread, while Excel is 'busy'.

The only workaround seems to be to retry (with some small delay) the COM call until it succeeds - when Excel is no longer 'busy'.

Check your start indexes. Its start from 1 not 0 for Microsoft.Office.Interop.Excel range objects. I had received same error because of my loop start value.

Go to Excel Options > Save > Save Files in this format > Select "Excel Workbook(*.xlsx)". This problem occurs if you are using an older version of excel file (.xls) instead of .xlsx. The older version does not allow more than 65k rows in the excel sheet.

Once you have saved as .xslx, try executing your code again.

edit ----

Looking more into your problem, it seems that the problem might be locale specific. Does the code work on another machine? What value does the cell have? Is it datetime format? Have a look here:

http://support.microsoft.com/kb/320369

http://blogs.msdn.com/b/eric_carter/archive/2005/06/15/429515.aspx