John is frustrated with the program called AirDroid to sync files back and forth from his mobile device and his PC. Leo says that there was a security flaw that would allow an attacker to intercept user data, so they changed the program to eliminate the bug. Unfortunately, as a result, it made the program pretty useless.
Leo says that Pushbullet may work, but there's also BitTorrent Sync by Resilio. It works from just about any platform back and forth. It uses a QR Code to sync the phone to the desktop. Another option is a cloud storage sync like DropBox, Google Drive, or OneDrive.
He could even just sync with a USB cable, or use an OTG cable to plug in a hard drive.
Leo uses a Synology Network Attached Storage (NAS) and software called Cloud Station to do it.