Ubutu grub boot loading menu not showing on Dual boot Windows 11

Surojit Manna

10/31/23, 3:18 PM

I have 2 hard drive. Windows & Ubuntu both have separated dedicated drive. But Ubuntu Grub menu doesn't show up in startup. I have checked on disk and it's clearly indicating that there have windows boot files and everything.

Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xa67451ca

Device     Boot     Start       End   Sectors   Size Id Type
/dev/sda1  *         2048   1050623   1048576   512M  b W95 FAT32
/dev/sda2         1050624 467521535 466470912 222.4G  7 HPFS/NTFS/exFAT
/dev/sda3       467521536 468856831   1335296   652M 27 Hidden NTFS WinRE


Disk /dev/sdb: 931.51 GiB, 1000204886016 bytes, 1953525168 sectors
Disk model: TOSHIBA DT01ACA1
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: C17AC212-7110-4A9F-B0A3-728932A315AE

Device       Start        End    Sectors  Size Type
/dev/sdb1     2048    1050623    1048576  512M EFI System
/dev/sdb2  1050624 1953523711 1952473088  931G Linux filesystem

I have tried to update the grub but it isn't showing Windows 11 on it.

~$ sudo update-grub
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.15.0-52-generic
Found initrd image: /boot/initrd.img-5.15.0-52-generic
Found linux image: /boot/vmlinuz-5.15.0-43-generic
Found initrd image: /boot/initrd.img-5.15.0-43-generic
Memtest86+ needs a 16-bit boot, that is not available on EFI, exiting
Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.
Adding boot menu entry for UEFI Firmware Settings ...
done

Any help would be highly appreciated.

342

1 + 4

partitioning

boot

grub2

dual-boot

mount

David

10/31/23, 3:37 PM

When you installed Ubuntu did it ask you install beside Windows?

Surojit Manna

10/31/23, 4:04 PM

Unfortunately no. It didn't asked in latest version on Ubuntu.

David

10/31/23, 4:06 PM

So it did not see the Windows install. So Grub can not make a dual boot menu if it does not see there are other OS already installed.

oldfred

10/31/23, 4:48 PM

Your sda is DOS or MBR partitioned. Windows only installs in old BIOS boot mode to MBR drives. Microsoft has required vendors to install Windows in UEFI boot mode to gpt partitioned drives since Windows 8 released in 2012, so almost all hardware is now UEFI. And it looks like Ubuntu may be UEFI/gpt. UEFI and BIOS are not compatible, once you start booting in one mode you cannot switch. Or grub can only boot other installs in same boot mode. Best to reinstall Windows in UEFI mode. But you can convert Ubuntu to BIOS boot mode if you add a 1MB bios_grub partition and reinstall grub in BIOS mode.

Score:0

Ubuntu

Joepie Es

10/31/23, 5:27 PM

Grub does not see your Windows installation because OS-prober is disabled.

See the statement in the output you posted:

Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.

In /etc/grub.d you can find a file called .script.sources.txt in which you can fix this problem. Delete the line that says disable 30_OS-prober or something similar and add the line "proxifiedScripts/os-prober";"30_os-prober" instead. Most likely the number will be 30. In the same folder you have all the different scripts, so you can check the number. You have to do this as root. Make backup of the file first and call it for instance .script.sources.txt.bck!!

The function of the OS_prober script is to search for other bootable Operating Systems.

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