EPPlus Error When Outputting .XLSX to Response
===

I have a weird issue here using EPPlus to create some .XLSX files. I have a package being created, and then being output to the response.

I have created a package as follows:

    var file = new FileInfo(@"C:\Test.xlsx");
    ExcelPackage package = new ExcelPackage(file);
    //...code to output data...//
    package.Save();

This saves the file to my local C: drive correctly, and when I open it it works great. No errors or anything, formatting is correct, etc...

However, I now wish to output this file to the response stream so I have modified the code I had to look like this:

    ExcelPackage package = new ExcelPackage();
    //...code to output data...//
    MemoryStream result = new MemoryStream();
    package.SaveAs(result);
    context.Response.Clear();
    context.Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";                                                       
    context.Response.AddHeader("Content-Disposition", "attachment;filename=MissionDetails.xlsx");
    result.WriteTo(context.Response.OutputStream);
    context.Response.End(); 

BUT when I run THIS code I get the following prompt when trying to open the Excel file:
**"Excel found unreadable content in filename.xlsx. Do you want to recover the contents of this workbook? If you trust the source of this workbook, click Yes"**

Clicking yes then displays the following prompt:
**"This file cannot be opened by using Microsoft Excel. Do you want to search the Microsoft Office Online Web site for a converter that can open the file?"**

I select no here and then it opens the Excel file and displays this error:
**"Excel completed file level validation and repair. Some parts of this workbook may have been repaired or discarded."**

BUT the file then loads fine and appears to be formatted correctly and everything. But every time I try to open the file it gives the same prompts and error message.

***NOTE:** The code to output the data does not change for either of these scenarios.

Has anyone seen anything like this? Or have any idea what could cause this to save the file incorrectly ONLY when outputting to the response?
