Volumes of a file system remain online, and thus available for use, while being proactively error scanned for corruptions thereon. A snapshot of each volume being proactively error scanned is maintained for the volume during the proactive error scanner processing of the volume. Proactive error scanner processing only requires access to file system metadata to correctly process a volume for an identification of the corruptions thereon, and thus, a snapshot of the entire volume nerd not be generated nor maintained. The clusters of a volume that store file system metadata are identified and only these clusters are maintained in a scoped snapshot for the volume during proactive error scanning of the volume.