This study explored Chinese heritage language learners' prior Mandarin experiences and their current Mandarin-learning experiences to reveal factors that influence their motivation and intention to continue or discontinue their Mandarin coursework. Using a Grounded Theory approach, we conducted demographic surveys and semi-structured interviews with eight participants taking beginner-level Mandarin courses. Following open, axial, and selective coding procedures, we developed a model portraying factors that influenced HLLs' decision to continue their enrollment in Mandarin classes. The model revealed that their decisions were fueled by ongoing appraisals via their motivational orientations, course expectations, and emotional experiences that drove their approach or avoidance focus. In particular, Mandarin high dropout rates may result from 1) HLLs' unmet course expectations, 2) lack of specific future-oriented instrumental values, and 3) unpleasant emotional experiences within the class. The study concluded with four pedagogical implications (e.g., adopting task-based language teaching) to sustain HLLs' motivation in college HL courses.