Hi,
I am afraid that i am not able to reproduce the problem that you have mentioned here. Please refer to the following steps that i tried to reproduce it.
1. I have created a sample in which i opened a file which is located on my desktop
using the following code snippet.
IWorkbook workbook = application.Workbooks.Open("C:\\Documents and Settings\\rajarajeswaris\\Desktop\\Book1.xls");
2. It opens properly without throwing any exception.
Please have a look at the video clip which explains you clearly about openning a file:
http://www.syncfusion.com/support/user/uploads/Open_440f18cb.zipPlease refer the sample from the below link which illustrates this:
http://www.syncfusion.com/support/user/uploads/Xlsio_32a3a6ec.zipPlease have a look at the above sample and if still the problem exists, could you please try reproducing it in the above sample or send us the reproducing steps so that we could sort out the cause of the issue and provide you a solution.
Regards,
Raji