An employee’s personnel file isn’t yet complete–do we still have to start paying wages?

Q: “At our company, we allow employees to begin working without handing in the documentation we require, such as reference letters or résumés. We always make sure we have the proper documentation such as I-9s, W-4s, etc. Are we legally allowed to hold an employee’s paycheck until their personnel file is complete? For example, we hold onto an employee’s check until they hand in their reference letter even though they have worked already.” – Michael, New York