You need to save your work periodically so you can continue with it later. Saving the project is different from exporting menu because instead of generating mode specific configuration files all builder's data is saved in product independent format.

This builder is a DHTML application and it runs in the secured environment of your browser. Due to default security settings (which you should keep unchanged) builder can't create any files in your local system so it will need a little help from you. Please follow the simple instructions in the left pane.