SmartScreen filter feature in IE9 protects users by warning against visits to malicious sites and downloading malicious software to their Computers, since all users don’t use IE9 to surf Microsoft ported SmartScreen with application reputation used in IE9 to Windows 8 developer preview which warns when users tries to run an application that has not well established reputation, SmartScreen gives a warning & recommends not to run it, delete the program or you can expand more details and click “Run this program and don’t prompt me again” to run the program anyway.
If you’re security savvy and download files from reputed sites, then you can turn off or disable Windows SmartScreen, here is how.
1. Open Control Panel>System and Security>Action Center
2. Expand Security section scroll down and click Change settings for Windows SmartScreen
3. Select Turn off Windows SmartScreen and click Ok to save changes.