When we compile a windows application(forms or sevice) in VS 2005 or VS 2008 then we see that there is a *.vshost.exe and *.vshost.exe.config file generated in the bin folder. And we wonder what are these files and why are they generated. Here (http://blogs.msdn.com/dtemp/archive/2004/08/17/215764.aspx) is the anser. In short they are there to provide support for improved F5 performance, partial trust debugging, and design time expression evaluation. These files are there just for developent environment. It sould not be deployed to production environment.