dexan mika mendes

    If you have dual booted kali with Windows 10 then most probably you are running PC with UEFI firmware. The booting process of UEFI is completely different from BIOS. Right after installation or after updating your UEFI you find that kali is not present in boot menu options. You can see the entry of Windows boot manager but there is no entry of kali in boot menu.

    The reason can be failed grub installation or Windows major updates.
    If you update UEFI it deletes the entry of kali from NVRAM.

    If you update UEFI from 1.x to 2.x then entry of Grub is removed from the boot-menu. Follow next post if you did this
    If you update UEFI from 1.x to 1.y then it remains there.

    Boot into kali live USB and follow the instructions:

    mount /dev/sda* /mnt
    mount --bind /dev /mnt/dev
    mount --bind /proc /mnt/proc
    mount --bind /sys /mnt/sys
    mkdir /mnt/sys/firmware/efi/efivars
    mount --bind /sys/firmware/efi/efivars /mnt/sys/firmware/efi/efivars
    mkdir /mnt/boot/efi
    mount /dev/sda+ /mnt/boot/efi
    mount -o remount,rw /dev/sda+ /mnt/boot/efi
    mkdir /mnt/hostrun
    mount --bind /run /mnt/hostrun
    chroot /mnt
    mkdir /run/lvm
    mount --bind /hostrun/lvm /run/lvm
    grub-install /dev/sda
    update-grub
    exit
    umount /mnt/dev
    umount /mnt/proc
    umount /mnt/sys/firmware/efi/efivars
    umount /mnt/sys
    umount /mnt/boot/efi
    umount /mnt/hostrun
    umount /mnt/run/lvm
    umount /mnt
    REBOOT

    /dev/sda* is your linux filesystem. Like mine is /dev/sda6
    /dev/sda+ is your EFI partition which is most likely /dev/sda1.
    Use fdisk -l to list all partitions.