This paper examines the risk of knowledge loss in managing public complaints. Drawing upon the literature on public complaint management and knowledge management (KM), in-depth interviews were carried out with the Public Complaint Bureau (PCB), a government agency responsible for handling public complaints. Interview data was meticulously recorded and transcribed to elicit an understanding of prominent factors of knowledge capture and knowledge organisation in handling public complaints. Focus-group discussions were also carried out to generate further insights. Documentation such Standard Operating Procedures (SOP), circulars and public reports were scrutinised to corroborate interview data. Research findings strongly indicate that inadequate knowledge capture and organisation have created a ‘black box’ in public complaint management. This black box has led to an ambiguous operating environment for PCB employees, caused by knowledge dissipation and evaporation. These issues stem from diverse individual knowledge practices and poorly designed knowledge flows within the organisation, resulting in significant knowledge loss. This qualitative research is expected to benefit organisations, mainly the government in improving knowledge capture and organisation practices by critically considering implementing KM efforts to avoid severe knowledge loss. It will also benefit the academic community for future reference.