List of main disadvantages. - If Sever develops a fault then users may not be able to run the application programs. - A fault in the network can cause user to lose the data. -If the network stops operating then it may not be possible to access to various computers. - It is difficult to make the system secure from hackers, novices or industrial espionage. - Decisions on resource planning tend to become centralized. - Networks that have grown with little thought can be inefficient in the long term. -As traffic increases on a network the performance degrades unless it is designed properly. - The larger the network becomes difficult to manage.