A method and system for managing access to add-on data files having an add-on data file attribute, which is used by a software application. The method: monitors input/output commands of the software application to an application programming interface of a code layer to determine whether an access to a data file with the add-on data file attribute is requested by the software application; checks whether an access code for the add-on data file is present in an access code list related to the software application if at least one of the monitored input/output commands request access to the add-on data file, if the access code is not present in the access control list; retrieves the access code from an external source outside of the access control list; and provides access to the add-on data file if the access code is present.