A central tenet of the open source software development methodology is that the community of users and developers is instrumental in improving the quality of software. Using a 10-year longitudinal dataset from the Firefox community, I investigate how the size of a community in terms of bug reporters and software developers, the social networks of developers and the quality of user contributions influence the time needed to repair software defects. The results show that a large open source community in terms of bug reporters reduces the time needed to resolve a defect while the addition of new software developers to an open source community takes away resources to fix bugs and increase the time needed to resolve a defect. In addition, software developers occupying dense network positions need less time to solve a bug. Finally, user contributions are beneficial when bugs are lively discussed but there is no support for the prediction that the experience of the bug reporter or the quality of the bug report reduces the time needed to solve a software defect.