The growth in the number of non-developer open source software (OSS) application users and the escalating use of these applications have led to the need for and interest in developing usable OSS. OSS communities do not usually know how to apply usability techniques in OSS development projects and are unclear about which techniques to use in each activity of the development process. The aim of our research is to determine the feasibility of applying User Profiles in the QUCS OSS project. To do this, we participated as volunteers in this project. We used the case study research method during technique application and participation in the OSS community. As a result, we identified adverse conditions that were an obstacle to technique application and modified the technique to make it applicable. We conclude that it was not easy to recruit OSS users and developers to participate in usability technique application.