An image forming apparatus includes a casing having a front end and a rear end, a first tray, a first print engine, a second tray, a second print engine and a controller. The controller configured to perform: receiving first image data representing the first image and second image data representing the second image; executing a first process including a first conveying process and a first recording process; executing a second process including a second conveying process and a second recording process; determining whether an error has occurred in the second process; and in a case where the error has occurred in the second process, stopping the second process while continuing the first process.