After producing a paper reel from the paper machine it must be converted to a form that is suitable for the use by customers. This operation called converting is carried out in Caledonian Paper by the winders located in the finishing area. Occasionally a problem may arise during the operation and various defects may appear on customer reels affecting the quality of the final product. The company suspected that the causes of deviations were profiles related and as the database of the mill contains a vast amount of profiles for both good and defective reels, specialists started investigations to find out a technology which would be able to extract a relevant and hidden information from the historical data. This information would then be used to predict a fault arising at the winders so that corrective actions could be applied before the defect becomes too significant. A CBR solution was chosen.