this problem occours whit Avast Internet Security,not whith AV.do you have AIS?i've tried in trial mode EVERY OTHER suite,and ONLY AIS create this problem,after uninstalling.
i have Windows 8 Pro x64.but i'm not the only user that have this problem.if you search with Google,you will see with your eyes.by the way: this problem must be solved,by Avast.