Properties.Settings.Default.Save() saves to which file?

This did bother me for a while.

There are two options for Scope when we try to add a setting. User and Application. Both default settings are stored in the app.config of this project.

Where will it be saved if user changes the setting in the running time?

The save will save to app.config of the project if it is a application level setting. But it will save to C:\Documents and Settings\[user]\Local Settings\Application Data\[application_name] folder if it is a User level setting.

You can only get the default setting back by deleting the XML files in the above folders and run your application.