An information processing apparatus capable of reliably accessing files associated with file identification information generated based on more character code systems, without necessitating a large-capacity memory. When the information processing apparatus (MFP) acquires file identification information, a CPU of the MFP determines whether or not the MFP is capable of performing processing based on a predetermined character code system used for describing the identification information. When the MFP is not capable of performing processing based on the character code system, the CPU converts the identification information described in the predetermined character code system into substitute character codes processable thereby. Then, the CPU registers the substitute character codes and the original character codes before the conversion in a map table in association with each other. When the processing on the file is completed, the CPU deletes the substitute character codes and the original character codes from the map table.