Limitations of graphical user interfaces, a program’s designed purpose, and other software development factors lead to perceived affordances and constraints in computer program functionality (Bell, 2015). Perceived affordances are functions the user knows exist, and constraints are limitations or restrictions to functionality (Norman, 2013). The perceived affordances and constraints of music creation programs may impact student compositions in many ways and have yet to be thoroughly investigated. The purpose of this study was to explore what effects students perceive music creation programs’ affordances and constraints have on their musical composing processes and final compositions. I interviewed, observed, and analyzed compositions from six students, ages 15-20, who had used music creation programs to compose. I used process and in vivo coding on these data to write descriptions of each student that highlighted their backgrounds, musical experiences, and how each student perceived the affordances and constraints in relation to their composing and compositions. I then used modified grounded theory analytical procedures to derive overarching themes from across all data. The students had difficulty describing how the affordances and constraints of the music creation software affected their composing and compositions. When students were able to describe program effects, these influences varied. The common effects were that the programs afforded the students testing for music ideas using the many available sounds and the students’ final compositions were a product of, or in spite of, those available sounds.