The default SettingsProvider for client applications (called the LocalFileSettingsProvider) stores settings in the application configuration files. In .NET v1 and v1.1, there were two levels of config files - machine.config and app.exe.config (where 'app.exe' is the name of the application). In v2.0, we have added two more levels of configuration to store user specific data - one that goes in the roaming user profile path and another in the local user profile path. On XP, the profile directories would be something like 'c:\Documents and Settings\<username>\Application Data' and 'c:\Documents and Settings\<username>\Local Settings\Application Data' respectively. These directories are the recommended location (per Windows Logo requirements) for storing user specific information, and most applications (like Outlook and Visual Studio) put user data somewhere under here.