Open terminal (Alt+Ctrl+T) and follow the below procedure :
- Paste the following command in terminal
sudo vim /etc/default/grub
(It will open a file named /boot/grub/grub.cfg file)
- Add GRUB_DISABLE_OS_PROBER=true at the bottom of this file.
It will prevent Windows being added to your grub menu.
- Now to write the change, run sudo update-grub
You can then run cat /boot/grub/grub.cfg to check that your Windows entry has disappeared.
Restart your device to check the same.