An image forming system and image forming apparatus capable of suppressing reduced productivity and avoiding the troublesome task of sorting output materials even when image formation becomes impossible. The system and apparatus include a transfer controller that permits job data transfer to another image forming apparatus if image formation of the job data has not started when an impaired image forming state is detected in an image forming apparatus, and that prohibits job data transfer to another image forming apparatus if image formation of job data has already started. In this way, the image formation process can be executed without processing congestion by having another image forming apparatus perform the job data image formation. Moreover, the task of sorting the output material is unnecessary because the job data is not dispersed between the transfer origin and the transfer destination.