Work-based learning is an influential period of teacher education, where a mentor teacher is assigned to support the student teacher. Mentoring conversations between the mentor teachers and student teacher seldom cover how student teachers cope with emotional challenges. Therefore, we aimed to investigate mentor teachers' perspectives on student teachers' reports of emotional challenges. The study had a particular focus on actions the mentor teachers described as preferable in reacting to scenarios of emotional challenges reported by student teachers. We conducted a constructivist grounded theory study and interviewed 22 mentor teachers. The findings of the study show that mentor teachers' main concern revolved around student teachers' understanding of challenges as learning opportunities. According to mentor teachers' descriptions, the preferred actions in their role as mentor teachers were to regulate, engage/help, be exemplary, and take charge. Thus, our study shows that mentor teachers intended to aid student teachers in navigating emotional challenges.