More and more companies are trying to optimize their corporate goals through digitalization. These include large corporations, medium-sized companies, but also small businesses. Starting with a central information system, companies are networking to obtain as much information as possible and to keep processes lean in order to increase sales and profits. The complexity of an ERP system often prevents complete transparency in use due to gaps in knowledge. This makes faster, simpler solutions from the common software shelf appear more attractive and is preferred by the user. The aim of this research is to determine the factors for the use of shadow IT. Thus, connections with general information systems such as an ERP system become recognizable. The research questions which are derived from this: What types of shadow IT exist in Germany and Serbia? What are the reasons for a use and do they entail risks? In order to be able to answer these questions, a thorough analysis of the applied software is required. In this case, this also includes an analysis from the user's point of view. These considerations are also differentiated regionally as well as content-related in the following research. Here, experts from European companies were interviewed. By means of a survey, participants were able to explain their use of additional software. This results in interpretations regarding the use of shadow IT. There is a clear trend towards the use of certain auxiliary software. In addition to the strengths and weaknesses of the shadow IT, this work also conveys the weak points of the standardized information system, such as the ERP system and its modules.