Files explorer hangs on Ubuntu 16.04.1 LTS - worked around by killing nautilus
Solution 1:
Try to remove it, do a repo/dependency cleanup, and reinstall it.
sudo apt-get remove nautilus
Cleanup:
sudo apt-get autoremove
sudo apt-get clean
sudo apt-get update
sudo apt-get upgrade
sudo apt-get install nautilus
Solution 2:
I solved this adding following lines:
vm.dirty_background_ratio = 5
vm.dirty_ratio = 10
into /etc/sysctl.conf
and running
sudo sysctl -p
Found in this thread: System freezes/unresponsive/unusable when copying large file to USB