Cannot open Excel file in C#

Question

I have the following C# function in my project, which is supposed to open and return an existing Excel workbook object:

Application _excelApp;

// ...

private W         


        

Answer 1

I had this issue today.

Surprisingly, it seems that the error occurred when the application was run as Administrator.

After we moved to Windows 10, some things (mainly related to IIS) would only work if running Visual Studio as Administrator, so it quickly became a habbit to start VS as Administrator.

The solution was to NOT run the application as Administrator.

This might be related to how our work environments are set up, but I thought it was worht sharing, if anyone else experiences the same issue, and the other solutions don't work for them either.