This Practice Note discusses the use of non-contractual devices by software suppliers to control the running of, or prevent improper use of on-premise software in business-to-business licences, the consequential legal issues, and the practical implications for the drafting of relevant software licences. It introduces time bombs, logic bombs, back-door/trap-door, fork locks, remote control and turning off, or ‘deprovisioning’. If a customer fails to comply with the licence terms, or to pay licence or support fees, the relevant software supplier will have a right to bring legal proceedings. But litigation carries cost and risk, as well as consequences for the relationship between customer and supplier. The supplier may therefore be attracted to a very direct practical option: the use of disabling devices, to prevent the software running, that can be remotely or automatically triggered by the supplier. For most software developers, these devices are easy to code and install. Triggering (or threatening to trigger) such devices may give the supplier a very powerful hold over customers, particularly