Non-rotating ('locked') magnetic islands often lead to complete losses of confinement in tokamak plasmas, called major disruptions. Here locked islands were suppressed for the first time, by a combination of applied three-dimensional magnetic fields and injected millimetre waves. The applied fields were used to control the phase of locking and so align the island O-point with the region where the injected waves generated non-inductive currents. This resulted in stabilization of the locked island, disruption avoidance, recovery of high confinement and high pressure, in accordance with the expected dependencies upon wave power and relative phase between O-point and driven current.The international ITER [1] tokamak has the objective of demonstrating the scientific feasibility of magnetic confinement fusion as a source of energy. A concern towards the achievement of this goal is represented by major disruptions [1]: complete losses of confinement often initiated [2] by a non-rotating ('locked') magnetic island created by magnetic reconnection [3]. During disruptions, energy and particles accumulated in the plasma volume over several confinement times (seconds in ITER, a fraction of a second in present experiments) are lost in a few milliseconds and released on the plasma-facing materials [4]. In addition, multi-MA level currents flowing in the tokamak plasma for its sustainment and confinement are lost, also in milliseconds, thus terminating the plasma discharge and causing electromagnetic stresses that, if unmitigated, could lead to excessive device wear. Here it is shown for the first time that magnetic perturbations can be used to avoid disruptions by "guiding" the magnetic island to lock in a position where it is accessible to millimetre wave beams that fully stabilize it. Stabilization is due to locally wave-driven currents (Electron Cyclotron Current Drive, or ECCD).Magnetic control of island rotation [5] and stabilization of rotating islands by ECCD [6] were separately demonstrated in the past. Currents were either continuously driven [6] or, more efficiently, they were modulated in synch with the spontaneous island rotation [7]. Electron Cyclotron Heating (ECH) was also used for stabilization [8], but is predicted to scale unfavorably to large hot plasmas [9]. Two experiments combined magnetic perturbations -to produce the island-with ECH that stabilized it: in the first one the mode was born locked to a given phase and was stabilized by continuous ECH [10]; the second one controlled island rotation and stabilized the mode by modulated ECH [11].However, if the rotating island (typically a spontaneous, pressure-driven 'Neoclassical Tearing Mode') is not preempted or stabilized (due for example to late intervention, misalignment, or insufficient power being used for this purpose), or if the island does not ever rotate at all, it becomes necessary to suppress the locked mode. This capability was numerically modeled [12], experimentally tested [13], and is fully demonstrated here for the first time. Without this...