Error when creating Zip file using DotNetZip: Unexpected end of archive

Question

I have a method that zips up one or more files using DotNetZip, and it has been working correctly. I received an error for the first time today and it appears to be related to the total size of the archive. Using the same 60mb .tiff image, I would add a few extra copies, test, repeat. It worked fine until about 10 images were added, then, when I opened the Zip file using WinRar, I would get the "Unexpected end of archive" error. Testing in this manner, I believe I've ruled out the problem being related to my code or the files (being corrupt or something). The code does not error, only WinRar. When I open the Zip file, there is only one file displayed with a size of "0." So it seems like some sort of size limit is being reached and it's not allowing the archive to be created. I just don't know which limit it is. Here is my code, if it helps:

HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ContentType = "application/zip";
HttpContext.Current.Response.AddHeader("content-disposition", "filename=" + "MyFileName" + DateTime.Now.ToString("MMddyyyy") + ".zip");

using (var zip = new Ionic.Zip.ZipFile())
{
    zip.MaxOutputSegmentSize = 819200; // I tried adding this and it did not fix the problem

    foreach (var file in files)
    {
        zip.AddFile(file.FileLocation, file.ZipFileDirectory).FileName = 
            (!string.IsNullOrEmpty(file.ZipFileDirectory) && (file.ZipFileDirectory != @"\")) ? 
                string.Format(@"{0}\{1}", file.ZipFileDirectory, file.FileName) : 
                file.FileName;
    }

    zip.Save(HttpContext.Current.Response.OutputStream);
}

Answer 1

Do you need to Flush the stream after your are done writing to it?

HttpContext.Current.Response.Flush();

EDIT:

Call HttpContext.Current.ApplicationInstance.CompleteRequest()