Music researchers are seldom at the center of attention as a user group within LIS. Thus, investigations of search possibilities for digitized music manuscript collections with a user perspective are lacking. Here, three digitized music manuscript collections (the Schrank II collection in Dresden, the Utile Dulci collection in Stockholm, and the Düben collection in Uppsala) are examined with regard to the accessibility of their contents to the target user group in two steps: First, music researchers are asked about their information seeking process and queries. They are observed in surveys, interviews, and think-aloud protocols. Second, the three retrieval systems are subjected to a performance evaluation by means of precision, recall, and F1 measures. The results show that music researchers are seeking information either with known-item searching, browsing, or subject search, yet the latter with considerably different subjects than, for example, in the domain of literature. In addition, while music researchers are expressing their satisfaction with the discovery systems, the observations from protocol analysis and the performance evaluation show that all three have issues in retrieving relevant documents for music-specific queries.