2 Replies Latest reply on Aug 5, 2014 11:06 AM by Yodeler

    Error #2044: Unhandled IOErrorEvent:. text=Error #2038: File I/O Error, Upload error #2038 on https

    vishal.upad008 Level 1

      down vote


      I am facing an issue in file upload in firefox. File upload works fine in all other browsers except firefox.

      The basic bug is that filereference.upload under https doesn't work in firefox. I am using the filereference upload to initiate the upload.

      In firefox, I get the following error:


      Error #2044: Unhandled IOErrorEvent:. text=Error #2038: File I/O Error.


      The same bug has been reported on:






      But, no working solution has been provided on any of them.


      My application uses SSL.. In my case, even the upload request wasn't being generated from firefox which I could confirm by seeing in browsers webc console's net panel, the upload URL was not being hit. I tried debugging server side code and request not even being reached to server. That means, may be Adobe flash runtime is blocking the upload request.
      However, when I ran application in IE, installed the self signed certificate of the application in IE, file upload ambigously and ofcourse amazingly, started working in firefox..

      The same issue has been reported on different forums including Adobe, stackoverflow and many others, but nowhere could I find any working solution.

      My application's front end is in flex and this bug is really very embarrassing. Please suggest some solution, if any.

      Firefox Flash plugin version I have tested it with are "" and "11.4.402.287"

      Client OS tested on: Windows Server 2003, Ubuntu 10.04


        • 1. Re: Error #2044: Unhandled IOErrorEvent:. text=Error #2038: File I/O Error, Upload error #2038 on https


          I got stuck on this kind of issue for a long time : all upload working fine except using IE using flash and https.

          In fact the issue was strangly on server side, I was using commons-fileupload from apache to handle my upload java side. It was in version 1.2. Switching to 1.3 has fix my issue. It has a bug reading the file size.


          • 2. Re: Error #2044: Unhandled IOErrorEvent:. text=Error #2038: File I/O Error, Upload error #2038 on https

            This is a bit old but I'll reply anyway for other people.


            Adobe Flash uses the Operating Systems certificate store to validate certificates for https on the client machine when using filereference upload.  Internet Explorer also does this, so it works with Internet Explorer.  However the other browsers use their own certificate store to validate https certificates so it fails on the other browsers.  The way around it is for the user to install the root and intermediate certificates in the browser certificate store of your https certificate.  I ended up providing a link to the root and intermediate certs and instructions on how to install for the users.  A less than ideal solution.


            We are slowly moving away from Flash on the web site, but it will be a couple of more years before we can rewrite this portion of the web site.  It s apparent that Adobe is either unable or unwilling to do anything with this issue.