By default, IIS can not upload large file size to the web server. For IIS 6 and IIS 7, the default maximum file size for upload is 4 MB and 28.6 MB respectively. IIS 7 will throw a 404 error (HTTP Error 404.13 - CONTENT_LENGTH_TOO_LARGE) if user upload file larger than 30MB. In order to allow for larger file size uploads, a few server changes are required.  You have three steps to increase the file upload limit:

1. Modify the maxAllowedContentLength setting in the web.config
You could increase the max file size by modify the maxAllowedContentLength setting in the web.config file: <system.webServer>
  <security>
    <requestFiltering>
      <requestLimits maxAllowedContentLength="2147483648" />
    </requestFiltering>
  </security>
</system.webServer>

With that maxAllowedContentLength, users can upload files that are 2 GB in size. This setting will work right away without restart IIS services.

2. Edit the request filtering feature settings and therefore the request limits using IIS manager

  • Open IIS Manager.
  • Choose the web site that you simply wish to configure.
  • Check that you're in features view per the button at the lowest of the manager.
  • Choose Requests Filtering and open it by double-clicking the icon. The Request Filtering pane displays.
  • From the Actions pane on the right hand side of the screen click Edit Feature Settings... link. The Edit Request Filtering Settings window displays.
  • In the Request Limits section, enter the appropriate maximum allowed content length (Bytes) then click the OK button.
  • Next, Restart IIS.

3. Manually edit the ApplicationHost.config file

  • Click start. In the start Search box, type notepad. Right-click notepad, and so click Run as administrator.
  • On the File menu, click Open. within the File name box, type %windir%\system32\inetsrv\config\applicationhost.config, and so open.
  • Within the ApplicationHost.config file, find the  node.
  • Take away the maxAllowedContentLength property. Or, add a value that matches the scale of the Content-Length header that the client sends as a part of the request. By default, the worth of the maxAllowedContentLength property is 30000000.
    For instance, modify the subsequent configuration information within the  section.

    <requestLimits maxAllowedContentLength ="<length>" />

  • Finally, Save the ApplicationHost.config file.