Embodiments include method, systems and computer program products for preventing unauthorized resource updates. In some embodiments, it may be determined that a mainframe computer is not within a service period. A control file may be obtained and decrypted. Using the decrypted control file, the mainframe computer may be determined to be authorized. An available resource update file may be selected based on a determination that the mainframe computer is authorized. An update to a resource of the mainframe computer may be facilitated based on the available resource update file.