There’s an annoying bug in almost every Linux distribution I’ve worked with. When your copying a large file to usb device (pendrive etc.) it hangs at the end (I mean it haaaaaaaaaaaaangs).
I’ve found a solution that works on Elementary and Ubuntu (at least).
Simply paste this two commands in your terminal:
sudo sh -c 'echo $((48*1024*1024)) > /proc/sys/vm/dirty_bytes' sudo sh -c 'echo $((16*1024*1024)) > /proc/sys/vm/dirty_background_bytes'
Add this to some kind of startup script and forget about transfer problems…