If your running a x64 bit Ubuntu or other Linux and find USB transfers hang at the end apply this fix:
echo $((16*1024*1024)) > /proc/sys/vm/dirty_background_bytes
echo $((48*1024*1024)) > /proc/sys/vm/dirty_bytes
I suggest you edit your /etc/rc.local file to make this change persistant across reboots.
sudo nano /etc/rc.local
Go to the bottom of the file and leave a space then paste in those two lines.
Save the file with ctrl + x then press y.
To revert the changes enter this in console and remove the lines in /etc/rc.local
echo 0 > /proc/sys/vm/dirty_background_bytes
echo 0 > /proc/sys/vm/dirty_bytes
More info and references: https://unix.stackexchange.com/questions/107703/why-is-my-pc-freezing-while-im-copying-a-file-to-a-pendrive/107722#107722
for those who dont have /etc/rc.local can use this:
sudo sysctl -w vm.dirty_bytes=50331648
sudo sysctl -w vm.dirty_background_bytes=16777216
For this to be persistent on Ubuntu add the following to my /etc/sysctl.d/99-sysctl.conf file.
vm.dirty_bytes=50331648
vm.dirty_background_bytes=16777216
original gist @ https://gist.github.com/2E0PGS/f63544f8abe69acc5caaa54f56efe52f