Bronodum I don't think you still require the answer but I'll answer anyway. Once activated with serializer, you can use it without any issue. No need to block internet access or configure local host file. Annoying update pop ups are known to happen and for some reason if the activation stops working try the below trick. Do a complete uninstall then install serializer first after that install office. It's known to work for some users who had problem with the other way of installation.