Purpose: The aim of this study was to delve into the obstacles preventing the effective management of tacit knowledge risks in South African public sector enterprises (PSEs) from the perspectives of human resource management (HRM) and knowledge management (KM). A perusal of the literature reveals that most South African PSEs are grappling with significant challenges related to potential tacit knowledge loss risks. Design/methodology/approach: The research utilised a mixed methods exploratory sequential design, collecting qualitative data through interviews with 20 HR managers in 9 PSEs and survey data from 585 questionnaires. The reliability of the data was tested, and thematic analysis was performed using Atlas.ti software. Findings: The study identified key barriers to effective tacit knowledge loss risk management in PSEs, including a silo mentality, organisational red-tape, knowledge as a power source, lack of recognition and rewards, KM awareness, cultures and structures, employment equity, fixed-term contracts, competing priorities for leadership, knowledge hoarding, HRM practices, and inadequate KM technologies and systems. These pressing issues need to be addressed to improve knowledge risk management (KRM) efforts in PSEs. Research limitations/implications: The exploration of organisational barriers was only limited to the tacit knowledge loss risks category, induced by human resource turnover in country-specific PSEs. Future studies could explore the organisational barriers and factors affecting other types of knowledge risks in PSEs or similar knowledge-intensive business enterprises across the globe using different samples and populations. Other similar studies could include strategic sectors of the economy such as energy generation, civil aviation, defence, mining and rail. The study contributes to the knowledge-based view and knowledge stickiness theories, and proposes an interdisciplinarity approach using mixed methods for future research on tacit knowledge loss. Practical implications: The research findings conclusively indicate that PSEs face the aforementioned barriers that hinder the effective implementation of the KRM system. This study identifies that key organisational barriers were mainly due to a lack of knowledge-driven HRM strategies in KM. To address these barriers, HR managers and other stakeholders must collaborate to ensure effective knowledge management and mitigate the negative impact of knowledge loss risks on organisational performance. Social Implications: The study highlights the importance of removing key barriers for improved KRM in PSEs. The improved KRM can enhance public service delivery efficiency, transparency and the accountability of PSEs by addressing socio-economic developmental issues in developing economies. Originality/value: Using South African PSEs as a case to address this challenge, the paper sought to explore key organisational barriers to effective knowledge loss risk management in organisations with a view to shaping discourse, policies, research, theories and practices in KM and HRM. Organisational barriers affecting the management of such risks remain unexplored in the extant body of knowledge and practice. [ABSTRACT FROM AUTHOR]