Identification and analysis of problems occurring in complex machine-building company production systems is a very crucial stage in the process of improving these systems. Effective production systems nowadays are a key to the success for this type of companies. On the basis of production system problem identification and analysis tools known from the subject literature (among others ASIS model, Ishikava (fishbone) diagrams, impact wheels, current reality tree, risk assessment mapping tools (FMEA), cause and effect diagrams), the Authors of this paper proposed their author's identification and analysis framework of problems occurring in machine-building enterprise production systems. The proposed tool is a specific hybrid of solutions known from the literature. This tool has been developed and successfully used within the frames of a project aimed at improving the production system of one of the Polish biggest machine building's sector manufacturer. Problem identification and analysis framework of production systems in machine-building companies developed within this project has been called Production System Virus Analysis (PSVA) for the reason of results presentation specific character. In this paper basic assumptions and methodology of the tool developed by the Authors have been included. Additionally, in the practical part the Authors present an example of PSVA adoption for problem identification and analysis in the production system of one of the Polish biggest machines building company.