I have done clean install recently of Ubuntu Desktop 15.04.

And I was able to log in to the graphical environment until I enabled "boot to text" like said there: How do I disable X at boot time so that the system boots in text mode?

1. commented out

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

2. added "text" to

GRUB_CMDLINE_LINUX="text"

3. uncommented

GRUB_TERMINAL=console

4.

sudo update-grub

5.

sudo systemctl set-default multi-user.target

Now system does not load gui, just text prompt.

When I want the GUI, I start it using

sudo systemctl start lightdm

graphical login prompt appear, but when I pass the password screen flickers and again password prompt appears.

I even reverted all changes back: grub file and

sudo systemctl set-default graphical.target

How can I log in to the GUI now, please?