Stuck at GRUB command line

This is what I see:

GNU GRUB version 2.02~beta2-9ubuntu1

Minimal BASH-like line editing is supported. For the first word, TAB lists possible command completions. Anywhere else TAB lists possible device or file completions.

grub> _

What should I do now?

I copied from eli's answer in Unix forum

Cause: boot process can't find the root partition

Solution

Please type ls This will show all partitions, and then type individual

ls (hd0,1)/
ls (hd0,2)/ 

... and so on, until you find like

(hd0,1)/boot/grub or (hd0,1)/grub

In case of EFI,

(hd0,1)/efi/boot/grub or (hd0,1)/efi/grub... now set the boot parameters accordingly, just type this with your number

set prefix=(hd0,1)/grub
set root=(hd0,1)
insmod linux
insmod normal
normal

now it would boot and please open the Terminal and put this command line

sudo update-grub ... it should boot correctly in the next time. If not, you have to go through the steps again. In other case, you might have to repair or install grub again, please look at this article.

My SW: Windows 10 and Ubuntu 16.04 dual boot

HW: HP Pavilion 15t

You got a problem with the bootloader. You should initialize kernel. First use command ls, then adjust the following commands according to it. In the place of hd0 write your disk and in 1 write your number.

grub> set root=(hd0,1)
grub> linux /vmlinuz-4.4.0-38-generic 
grub> initrd /initrd.img-4.4.0-38-generic
grub> boot

If you don't know what your version of the kernel is, write:

grub> linux /vmlTab
grub> initrd /inTab

FIRST try only grub> boot

Not a permanent fix, but you should be able to continue just by exiting:

grub> exit

This will continue to either the grub menu (if you have a dual boot system) where you can choose which OS you want to boot, or directly to your primary operating system. This is a common problem with dual booting a system with UEFI bootloader.