A method of processing an electronic file by identifying portions of content data in the electronic file and determining if each portion of content data is passive content data having a fixed purpose or active content data having an associated function. If a portion is passive content data, then a determination is made as to whether the portion of passive content data is to be re-generated. If a portion is active content data, then the portion is analyzed to determine whether the portion of active content data is to be re-generated. A re-generated electronic file is then created from the portions of content data which are determined to be re-generated.