Assume that you run a WebBrowser Control-based application to download a file in Internet Explorer 9. Additionally, you use a "Content-disposition: attachment" HTTP header in the WebBrowser Control-based application. In this situation, the file does not download.
Note If you change the "Content-disposition: attachment" header to "Content-disposition: inline", this issue does not occur.
Security update information
To resolve this issue, install the most recent cumulative security update for Internet Explorer. To do this, go to the following Microsoft website: