you won’t believe it – but your password is NOT required.

all you have to do is find „#autologin-user“ and put your „autologin-user=username“ into it and <- UNCOMMENT autologin-user-timeout=0. reboot. works.

uname -a; # tested with
Linux debian 3.16.0-4-686-pae #1 SMP Debian 3.16.7-ckt25-2+deb8u3 (2016-07-02) i686 GNU/Linux

dpkg -l|grep mate-desktop
ii  libmate-desktop-2-17:i386             1.8.1+dfsg1-3+deb8u1                 i386         Library with common API for various MATE modules (library)
ii  mate-desktop                          1.8.1+dfsg1-3+deb8u1                 i386         Library with common API for various MATE modules
ii  mate-desktop-common                   1.8.1+dfsg1-3+deb8u1                 all          Library with common API for various MATE modules (common files)
ii  mate-desktop-environment              1.8.0+9                              all          MATE Desktop Environment (meta package)
ii  mate-desktop-environment-core         1.8.0+9                              all          MATE Desktop Environment (essential components, meta package)
ii  task-mate-desktop                     3.31+deb8u1                          all          MATE

vim /etc/lightdm/lightdm.conf;

[SeatDefaults]
#type=xlocal
#xdg-seat=seat0
#pam-service=lightdm
#pam-autologin-service=lightdm-autologin
#pam-greeter-service=lightdm-greeter
#xserver-command=X
#xserver-layout=
#xserver-config=
#xserver-allow-tcp=false
#xserver-share=true
#xserver-hostname=
#xserver-display-number=
#xdmcp-manager=
#xdmcp-port=177
#xdmcp-key=
#unity-compositor-command=unity-system-compositor
#unity-compositor-timeout=60
#greeter-session=example-gtk-gnome
#greeter-hide-users=false
#greeter-allow-guest=true
#greeter-show-manual-login=false
#greeter-show-remote-login=true
#user-session=default
#allow-user-switching=true
#allow-guest=true
#guest-session=
#session-wrapper=lightdm-session
#greeter-wrapper=
#guest-wrapper=
#display-setup-script=
#display-stopped-script=
#greeter-setup-script=
#session-setup-script=
#session-cleanup-script=
#autologin-guest=false
autologin-user=YOUR_USERNAME <- UNCOMMENT THIS LINE AND PUT YOUR USERNAME HERE
autologin-user-timeout=0 <- UNCOMMENT THIS LINE
admin