Ardour only allows you to work on one session at a time (although your computer may be able to run multiple instances of Ardour at one time). This means that to work on a different session than the current one, you will be forced to close the current session. You can either Session Close will close the current session. Session Open will prompt you for the name of a session to work on, and will then close the current session. Session New will open the New Session dialog to collect configuration information for the new session, and will then close the current session. Whenever a session is closed but has been modified since last saved, the Save dialog will appear. You have three options when this dialog appears: Save the session before closing it Close the session without saving it Do not close the session If you choose the final option, whatever operation initiated the closing of the session will be stopped. For example, if you were loading a new session while working on an existing one, no new session will be loaded.