A computer determines whether destination information is included in permission target information. The destination information indicates a destination to which a file stored in a storage device is transferred. The permission target information includes information indicating a target permitted to access the file. The computer prompts before the file is transferred, upon determining that the destination information is not included in the permission target information, a user to input whether to permit the transfer. The computer adds the destination information to the permission target information upon receiving, via an input device, a permission input for permitting the transfer. The computer transfers the file upon receiving the permission input.