Better solution from a user at Ask Ubuntu: set "HandleLidSwitch=ignore" in /etc/systemd/logind.conf.
http://askubuntu.com/questions/613448/when-i-install-ubuntu-15-04-the-computer-hibernate
This solves the problem completely.
Better solution from a user at Ask Ubuntu: set "HandleLidSwitc h=ignore" in /etc/systemd/ logind. conf.
http:// askubuntu. com/questions/ 613448/ when-i- install- ubuntu- 15-04-the- computer- hibernate
This solves the problem completely.