SDL core Caches the file names and responds to 'ListFiles' Request from [Cache](https://github.com/smartdevicelink/sdl_core/blob/master/src/components/application_manager/src/commands/mobile/list_files_request.cc#L80) instead of Enumerating through the file system. Issue is, There is possibility that System(HU) delete files, in that case 'ListFiles' response is invalid.