Like many other security features introduced by Microsoft to its Operating System’s build like User Account Control (UAC) to Windows 7 and Windows 8, it has again introduced another application filter tool called SmartScreen filter for Windows 8 Developer Preview that provides warning messages while visiting a phishing website or running a unsecure applications.
This feature seems to be most annoying when user runs even an uncategorized or secured application; in any case it just blocks it and not allows user to access it and also creates headache when each time it is displayed with the SmartScreen filter windows.
To turn off SmartScreen Filter, open the control panel and move to the Action Center and select Change SmartScreen Settings option from left side menu.
Now, a new Window screen wills pop-up with three options for unrecognized programs, select the last one which says Turn off Windows SmartScreen and hit OK button.
Although, SmartScreen filter is just an application that provides a security feature like that of UAC but Microsoft should must provide an option to add those recognized or trusted application to it.