I was having the same problem, and updating to 16.04.2 was the solution for me, specifically
sudo apt-get -y dist-upgrade
given that I was already running 16.04. The problem had also been reported here
https://askubuntu.com/questions/835556/network-manager-doesnt-remember-login-username/913179?noredirect=1#comment1438576_913179
and solved the same way. I'd suggest that this bug be considered closed.
I was having the same problem, and updating to 16.04.2 was the solution for me, specifically
sudo apt-get -y dist-upgrade
given that I was already running 16.04. The problem had also been reported here
https:/ /askubuntu. com/questions/ 835556/ network- manager- doesnt- remember- login-username/ 913179? noredirect= 1#comment143857 6_913179
and solved the same way.
I'd suggest that this bug be considered closed.