What is the result of this code that Firefox receives via the HTTP response headers if you check that with the Live Http Headers extension?

• https://addons.mozilla.org/firefox/addon/live-http-headers/

Below are the results from Live Http Headers. Thanks for your assistance.

HTTP/1.1 200 OK Date: Wed, 05 Nov 2014 15:52:32 GMT Server: Microsoft-IIS/6.0 MicrosoftOfficeWebServer: 5.0_Pub X-Powered-By: ASP.NET X-AspNet-Version: 4.0.30319 Pragma: no-cache Content-Disposition: inline; filename=E:\CustomerData\testfil.pdf Transfer-Encoding: chunked Cache-Control: private Content-Type: application/pdf

Thanks cor-el. You pointed me in the right direction. It appears to me that a reported Firefox 33 bug with the handling of compression (Transfer-Encoding: chunked) is the culprit (https://support.mozilla.org/en-US/questions/1026743). I was able to find a work-around by specifying the file size and buffering. Below is my code, with some code from http://www.codeproject.com/Questions/440054/How-to-Open-any-file-in-new-browser-tab-using-ASP.

           Dim strPDF As String
           strPDF = Session("filname")   'pdf filename

           Dim User As New WebClient()
           Dim FileBuffer As [Byte]() = User.DownloadData(strPDF)
           If Not (FileBuffer Is Nothing) Then
               Response.Clear()
               Response.ClearHeaders()
               Response.CacheControl = "Private"
               Response.AddHeader("Pragma", "no-cache")
               Response.AddHeader("Expires", "0")
               Response.AddHeader("Cache-Control", "no-store, no-cache, must-revalidate")
               Response.ContentType = "application/pdf"
               Response.AddHeader("content-length", FileBuffer.Length.ToString())
               Response.BinaryWrite(FileBuffer)

               Response.Flush()
               Response.Close()
               Response.Clear()
               Response.End()
           End If
           Session("filname") = ""

My problem is different. After updating I tried to display the Banks statement which starts the Adobe PDF reader and then never displays the file. Just a little circle going round and round. I can save the file and double click it to display the file in reader but it will not display in Firefox. Works in IE also.

Hi bmazak, you're right that it's a different problem. Would you mind starting a new question here: https://support.mozilla.org/questions/new/desktop/fix-problems - scroll down past the suggested articles to continue with entering your question.

Also, if you haven't tried using a different viewer, you could check out this article: View PDF files in Firefox or choose another viewer.