Turnover of volunteer members and the ensuing instability bring about severe problems to open source software (OSS) projects. To better understand it, we based our study on Herzberg ́s two-factor theory to investigate the influence of hygiene factors on volunteer members ́ dissatisfaction and perceived turnover. After empirically testing the research model, we found shortcomings in project regulation and administration are the key reason for volunteer members ́ dissatisfaction, followed by future rewards and personal needs for software functionalities. By contrast, a possible lack of supportive working relationship among OSS developers was not found to be a trigger for developer dissatisfaction. Dissatisfaction was confirmed to be a significant predictor of perceived turnover. The results demonstrates generalized hygiene factors cannot unreflectively be transferred into the OSS context because volunteer members ́ personal expectation has a weaker influence on perceived turnover than objective attributes of OSS project. Our study further makes suggestions for project administrators.