How to recover gnome-shell

If you found that your gnome-shell task bar missing?
And your desktop seems plain and not able to access applications menu.
You can recover your lost desktop. Follow the steps.

Apply the key combinations, Ctrl + Alt + T 
A terminal will open. Enter the following commands,

sudo su
gnome-shell --replace

You can see that, your desktop panels and menus appear again

Change grahical Ubuntu boot splash into text mode

gedit /etc/default/grub

Find the word "quiet splash".
Remove the word "quiet splash".

Save the file.

Update the grub.

update-grub