18.04 dual boot showing grub2 manual

Question

Did a fresh install of 18.04 alongside Windows 10 (UEFI). Now my system boots only into grub2 commandline.

I am able to boot into both windows by executing

chainloader **(hd0,gpt1)**/efi/Microsoft/bootmfgw.efi

and ubuntu by executing

set prefix=(hd0,gpt6)/boot/grub
set root=**(hd0,gpt6)**
insmod linux
insmod normal
normal

I ran grub-install, boot repair several times after booting into ubuntu, but to no effect. I still keep booting into grub commandline.

Any help is appreciated. Boot repair pastebin - http://paste.ubuntu.com/p/64X9XmshBJ

Screenshot of gparted:

I have tried these, and it did not work:

grub-install with grub-efi-amd4
grub install from live usb
boot-repair from live usb or ubuntu
fresh install of 18.04 again lands in grub manual

once you are in Ubuntu with above commands, can you provide a pic after opening "GParted" — PRATAP, Jul 10 '18 at 16:08
@PRATAP Screenshot of gparted https://drive.google.com/file/d/1dX_aCj9LK9bi8XuKO9SVLndlCUeOuaCL/view?usp=sharing — jayendra.rakesh, Jul 10 '18 at 16:15
also dump of one of the boot-repair attempts - http://paste.ubuntu.com/p/64X9XmshBJ/ — jayendra.rakesh, Jul 10 '18 at 16:19
can you click on sda2 "red color alert" and paste the error? — PRATAP, Jul 10 '18 at 16:21
It says warning ! - Unable to detect file system! Possible reasons are:

The file system is damaged

The file system is unknown to GParted

There is no file system available (unformatted)

The device entry /dev/sda2 is missing — jayendra.rakesh, Jul 10 '18 at 16:24
/sdb is my 2 TB hard disk with ntfs partitions for storage and games. /sda is the SSD — jayendra.rakesh, Jul 10 '18 at 16:29
Ok, have you tried Boot-Repair with live session? that could solve the thing. if not, you may need to delete that partition sda2 red color alert. First try Boot-Repair with live session. — PRATAP, Jul 10 '18 at 16:34
Or you can first try the answer in this question. https://askubuntu.com/questions/1042813/installation-of-windows-10-ubuntu-18-04-ubuntu-18-04-windows-10 — PRATAP, Jul 10 '18 at 16:40
@PRATAP should I install the grub in /sda or /sda1(where my existing efi files are) ? — jayendra.rakesh, Jul 10 '18 at 16:51
you should select /sda for grub install command. sudo grub-install --recheck /dev/sda — PRATAP, Jul 10 '18 at 16:52
Error on your sda2 is normal. It really should not be an error as it is a required partition by Windows. But gparted sees it as unformatted so flags as an error. Since it has a valid GUID for Microsoft Reserved partition, gparted should know it is valid. Have you tried a full uninstall/reinstall of grub using Boot-Repair? See this thread. https://askubuntu.com/questions/1053895/system-always-boots-to-grub-prompt?noredirect=1#comment1722812_1053895 — oldfred, Jul 10 '18 at 16:59
@jayendra.rakesh please ignore my comment where i suggested to delete sda2. I agree with Mr. oldfred. — PRATAP, Jul 10 '18 at 17:02
See this. It looks like they rolled out newer grub with bug that supposedly is fixed in 18.10. Ubuntu 18.10 Cosmic installed /EFI/grub https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1775743 Also: https://ubuntuforums.org/showthread.php?t=2396042 & https://askubuntu.com/questions/1053895/system-always-boots-to-grub-prompt?noredirect=1#comment1722812_1053895 — oldfred, Jul 10 '18 at 19:20

Carlos M. · Accepted Answer · 2018-12-02T19:20:33.870

When using windows 10 on sda3 and you install and boot ubuntu 18.04

sudo blkid
 (read uuid from /dev/sda3, used below as uuid_read_above)

sudo nano /etc/default/grub
 (add line to the end of the file:)
    GRUB_PRELOAD_MODULES="part_msdos"
sudo update-grub

sudo nano /etc/grub.d/40_custom
 (add these lines to the end of the file:)
    menuentry "Windows 10" {
     insmod ntfs
     set root='(hd0,3)'
     search --no-floppy --fs-uuid --set uuid_read_above
     ntldr /bootmgr
     chainloader +1     
    }
sudo update-grub

sudo grub-install /dev/sda
sudo update-grub

exit and boot from hdd, should see menu with "Windows 10"

boot dual-boot grub2 uefi 18.04 grub-efi grub-pc windows-10 ntfs

18.04 dual boot showing grub2 manual

1 Answers1