Changing automatized motor skills is a challenging endeavor. While often intended to raise or re-establish performance levels, this process is frequently associated with initial performance decrements. In this context, proactive interference has been theorized to play a particular role, as an already well-established and automatized procedural skill often hampers the acquisition or recall of the new target behavior. As a consequence, individuals must usually first overcome this interference which often renders skill change processes time-consuming and effortful. Despite its high practical relevance, there is only little research that has systematically investigated this topic so far. The aim of the present thesis was therefore to scrutinize the underlying mechanisms of proactive interference and its associated performance decrements in motor skill change. A multidisciplinary approach was pursued by empirically examining several individual and task-related factors which have been hypothesized to affect the amount of interference. To this end, a novel experimental paradigm was established which addressed the highly automatized motor skill of typing on a computer keyboard and that allowed to induce interference intentionally via different types of rule changes. In four experimental studies, including behavioral assessments, cognitive tests, eye-tracking and electroencephalography, several factors were identified to be associated with successful interference control in motor tasks: age, proficiency and prepotent response inhibition. Furthermore, there was a tendency towards a benefit of a motor restriction that limits individual motor degrees of freedom which might function as a potential inhibition support. These results provide first insights into the cognitive and electrophysiological mechanisms underlying motor skill modifications which in the long run might help to optimize motor skill change processes.