Ubuntu – How to hide the GRUB menu showing up at the beginning of boot

This might be a problem of broken grub. Grub is basically a boot loader. In other words it is the screen that comes up with options to start Windows or Ubuntu. I had a very similar problem. In my case I had dual booted Mint and Ubuntu. To fix the grub, check this.

First try to change the boot order in BIOS (UEFI) settings.
Select Ubuntu to be the default operating system to boot.

If this is not possible boot into Windows and disable hibernation and Fast Boot.

To disable hibernation open command prompt as administrator and execute this command:

powercfg /h off  

To disable Fast Boot open Control Panel (the old version - not the modern design),
select the Energy Settings, enable show hidden settings and uncheck Fast Boot.

After having done this shutdown the machine completely - do NOT reboot!

Then reinstall the GRUB boot loader to your Ubuntu installation in EFI mode.

Boot from the Ubuntu installation media - then open a terminal and execute:

sudo mount /dev/sd*** /mnt
sudo mount /dev/sd** /mnt/boot/efi
for i in /dev /dev/pts /proc /sys /run; do sudo mount -B $i /mnt$i; done
sudo chroot /mnt
grub-install /dev/sd*
update-grub  

Now you can choose which operating system you want to boot from the GRUB boot loader menu.

Note :

sd* = disk | sd** = efi partition | sd*** = system partition

To identify the partition numbers use GParted.
The tool is included in the Ubuntu install media.