Why can't I change application scoped settings at runtime?

Application scoped settings are essentially read only from the application's point of view, and aren't meant to be changed by users, but rather only the administrator. An additional reason for this has to do with how the default SettingsProvider stores settings. Application scoped settings are stored in the exe configuration file, and user scoped settings are stored in user.config files located in the user data path. Generally, exe config files should not be written to at runtime by the application, since the user may not have access to them. In addition, it is normally not a good idea for a user to change a file that affects every other user of the application.

Technorati : dotnet, faq, framework, microsoft