Provided are a data generation apparatus capable of generating data for preview display with a replaced part being easily recognized and a data generation method. The data generation apparatus includes: a communication section configured to communicate with a print instructing apparatus which sends print job of a document; and a preview image generating section configured to analyze the print job received through the communication section and generate a preview image with pages of the document reflecting printing settings. The preview image generating section is further configured to determine whether or not an object having a property not supported by the data generation apparatus exists in each page of the document; in response to determining that the object exists, obtain a possible alternative to the property of the object; generate edit data to be used for highlighting a replaced part in the preview image in which the property of the object is replaced with the possible alternative; and output the edit data to the print instructing apparatus so as to allow a user to recognize the replaced part of the preview image.