Song Master and Song Master Pro apps will automatically enter Trial mode if they have not been purchased and registered. Trial mode enables you to try out Song Master before purchasing to determine if it meets your needs. Trial versions let you try out all of Song Masters' features, but you will be time-limited to 15 minutes per run and you won't be able to save any changes you make. 

When you purchase Song Master, you Unlock it to the full version by registering it within the app. You can register it when you first start Song Master or from the Help menu. Your registration key is the user email and password that you used when you purchased Song Master.