How can an employer recover overpayment from a terminated employee?

The only legal way to recover the overpayment, if the employee will not voluntarily pay it, is to sue the employee for the money; the problem is, the law does not allow an employer to deduct amounts an employee owes from any paychecks (including final paychecks or severance) or withhold those checks, unless the employee consents to the deduction. This leaves a lawsuit as the only way to get the money.