The installation of multiple applications by an installer is executed in a mode that does not display an error message in a display device. Upon an installation performed by the installer ending, the result of the installation performed by the installer is determined. As a result of the determination, an installer that failed at the installation is caused to re-execute the installation of the application whose installation failed in a mode that displays an error message in the display device. As a result of the re-execution, an error message is displayed in the display device by the installer that failed at the installation.