Copy, move, sync and backup your mp3, pictures and documents over WiFi, USB tethering, cellular VPN or wired network to your computer or NAS device. Nothing to be installed on your computer. Sync automatically even before you enter your home with 'If connected to WiFi router'.

SHARING MUST BE ENABLED ON YOUR COMPUTER, the simplest way to do this on Windows is to right click the folder you wish to synchronize select Share With and go with the instructions. Restart of the PC sometimes is needed when sharing for the very first time.

Features:

Two and one-way sync.
Sync deletions.
Schedule sync by combination of interval, exact time of the day, weekday, when device connects to a specific WiFi router and when power charging.
Include/exclude filter for hidden, read protected, individual files/folders, file name pattern, file type (extension), file date.
VPN and Portable WiFi Hot Spot over cellular connections.
Wake up PC (WOL) either manually or on a scheduled sync.
Organize pictures by date and/or address.
Organize mp3 music by artist and/or album and rename to the original song name.
Cut, copy, paste, preview remote and local files.

Uses Windows shares, Samba on Linux and older Macs, CIFS (SMB) protocol.

Hidden sneaky costs: There are four premium (paid) features in this app: 1) Schedule with router 2) Weekly schedule 3) Include/Exclude directories and files, new extensions and regular expressions 4) Wake up PC before sync. One time donation covers them all and any upcoming premium feature.

Known issues:
1) Insufficient resources error on Windows:
Check file path on Windows, paths are limited to 260 character after long files names were replaced with their short names.
Also looks like Windows sometimes is not fast enough to reclaim resources. Changing registry seems to help: "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\LanmanServer\Parameters\Size" 3