The production of an individualized product at the request of an individual customer is associated not only with maintaining the continuity of the production system, but also with the proper organization of the production process. The authors show the disturbances resulting from the production system of a manufacturing company with a high degree of customization, and also present the impact on the planned production plans. As a result of the research, the categories of disturbances reported as so-called unplanned times, as well as their percentage in the context of the production system’s operation and potential causes.