Debian not booting into GUI

The program where you type your user name and password in a graphical environment, and that logs you into a graphical session, is called a display manager. You need to install a display manager. On Debian, if you install any of the display manager packages then one of them will be started at boot time.

Any of the packages that provide the x-display-manager virtual package will do. As of Debian jessie, that's gdm3 (Gnome), kdm (KDE), lightdm (lightweight but themable), slim (lightweight but themable), wdm (lightweight but themable, oldish), xdm (old-style, bare-bones). You don't have to use a display manager that matches your desktop environment. If in doubt, pick lightdm.

I was also confused by this problem for a long time. Reading the documentation from Debian wiki, at last, I finally found a way out.

# systemctl status gdm

# systemctl start gdm

and then I can access GUI again. Reference:

• https://wiki.debian.org/GDM#systemd

First of all GNOME is already there, but by default it is off.

To reset your login manager so that it runs gnome at boot up, do (as superuser)

update-rc.d -f gdm3 defaults

Or you can re-install and select the proper options

You can install the GUI easily:

apt-get install gnome