System control

A method of controlling system critical changes implementable by a user of an operating system, a computer program product and an operating system operable to perform that method. The method comprises: receiving a request from a user to make a system critical change; assessing whether the user has appropriate privileges to make the system critical change; and, if so, notifying at least one further user having appropriate privileges to make the system critical change of the received request; and awaiting approval from at least one further user before implementing the requested system critical change. Aspects and embodiments improve security of a computer system by removing single user's capability to directly issue and have implemented dangerous or disruptive commands.