An information processing system includes one or more devices configured to operate based on setting information for controlling an operation; and at least one external device configured to change the setting information of the device. The external device includes circuitry configured to: acquire the setting information of the device, generate change information obtained by changing the acquired setting information, and set the change information in the device. The device includes circuitry configured to: acquire the setting information from a setting storage and transmit the acquired setting information to the external device, acquire the change information in the external device, and rewrite original setting information stored in the setting storage to the acquired change information.