Comment 13 for bug 1512002

// take from http://ubuntu.itsprite.com/ubuntuseemingly-random-authentication-is-required-to-change-your-own-user-data/

This worked to me:

1) At Settings -> Session and Startup ( Application Autostart TAB )

Session and Startup

Uncheck PolicyKit Authentication Agent

( /usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1 )

2) In a Terminal:

1
sudo killall polkit-gnome-authentication-agent-1
My Desktop was running:

Distributor ID: Ubuntu
Description: Ubuntu Wily Werewolf (development branch)
Release: 15.10
Codename: wily