Maybe the program you are trying to debug is using admin privileges but visual studio doesn't have admin rights.
run visual studio as administrator, even if you are logged in as administrator it doesn't automatically have admin privileges.
you can do this quickly by right clicking on the short cut of Visual Studio and click Run as Administrator.
Or you can make it automatically run as admin by right clicking the shortcut and choosing properties. Choose Compatibility -> Privilege Level -> Run this program as administrator