What happens once Head Start processing begins for email programs?

When Head Start processing begins for email programs in Marketo, the program becomes locked and cannot be changed. This is important because it prevents any modifications that could alter the integrity of the email being sent. Once the Head Start processing is initiated, the system prepares the email for distribution, ensuring that all data, personalization, and configurations are finalized for accurate delivery. Locking the program at this stage helps to prevent potential errors that could arise from last-minute changes, thereby maintaining a consistent and reliable send process.