It costs money to move corporate information, including customer and supplier records, product design data and the like, from the old systems to the new ERP system. A lot of data in most legacy systems is redundant. But most companies seem to deny that a vast amount of their data is useless until they actually have to move it to the new client/server setups that popular ERP packages require. As a result, these companies are more likely to underestimate the cost of the move. But even clean data may demand some overhaul to match the process modifications necessitated or inspired by the ERP implementation.