A method of safeguarding a machine is provided in which objects are recognized in a work zone of the machine in which a contactless distance sensor that is moved along measures an actual measured value for a distance with at least one distance measurement beam, a first virtual distance measurement beam that simulates the distance measurement beam is formed, and the actual measured value is compared with its first virtual measured value. In this respect, at least one further virtual distance measurement beam having an offset from the first virtual distance measurement beam is formed and a further virtual measured value is calculated with it and a comparison is made whether the actual measured value is compatible with the virtual measured values.