Why can’t grub find the disk by UUID?

I’m trying to troubleshoot why I can’t boot to Windows.

The relevant entry in grub.cfg is:

### BEGIN /etc/grub.d/30_os-prober ###
menuentry 'Windows Boot Manager (on /dev/sda3)' --class windows --class os $menuentry_id_option 'osprober-efi-BC6E-0415' {
        insmod part_gpt
        insmod fat
        set root='hd0,gpt3'
        if [ x$feature_platform_search_hint = xy ]; then
          search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt3 --hint-efi=hd0,gpt3 --hint-baremetal=ahci0,gpt3  BC6E-0415
        else
          search --no-floppy --fs-uuid --set=root BC6E-0415
        fi
        chainloader /efi/Microsoft/Boot/bootmgfw.efi
}

Best I can tell, everything here is correct:
/dev/disk/by-uuid/BC6E-0415 is indeed the Windows boot manager partition.

However I’m slightly confused by the references to (hd0,gpt3) because that’s a completely different partition on a completely different physical disk. hd0 is the disk on which grub is installed though, in case that’s relevant.

The actual error I get when I try and boot Windows is:

error: no such device: BC6E-0415
error: file `/efi/Microsoft/Boot/bootmgfw.efi' not found

I do notice that in grub, if I drop to a grub command prompt and do an ls, the only hard disk I see listed is hd0 when my system actually has 4 hard disks. As I mentioned above, hd0 is the hard disk that has grub and my Linux installs.

So I think my question might be: why, when I boot to grub, can’t grub see any hard disks besides the one grub is on?

If I boot into Linux (Ubuntu 20.04.1) I can see all my hard disks just fine.

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Author: Bridgey

GRUB not picking up windows boot manager which is in another drive

Ubuntu 18.04 LTS and Windows 10
I have a laptop that has an SSD and a hard drive
Windows is on the SSD and Ubuntu on the Hard Drive
I made a separate EFI partition while installing ubuntu using the “Something Else” option
When I boot my laptop I have to press “Esc” key to enter GRUB and it does not pickup the windows boot manager
Moreover, Ubuntu is not detecting the SSD
What to do ?
Please ask for any additional info required

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Author: Tanmay Bhatnagar

Can’t open GRUB in ubuntu 18.04

Its a dual boot i.e. windows 10 and ubuntu 18.04. Ubuntu is filled as preferred choice hence GRUB doesn’t come by default.
I went through many resources available and they all said press shift before the logo of ubuntu appears i.e. while the manufacturer logo is there in the screen( in my case its Lenovo ).
I have tried tapping shift continuously , long pressed shift and even kept it pressed before turning the computer ON but in none of the cases GRUB window opened. Have tried it with both left as well as right shift.I am trying to open ubuntu’s recovery mode.

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Author: Aaryan Gupta

Unexpected SPC Access Width error returning to default e

What’s happened: I have modified the fstab file. My aim was to mount an external hard disk permanently. I duly changed the username, but forgot to change the “sdb4″ to sdb1” in the command line and pasted it to a terminal window. Now Ubuntu does not boot, I am on a choo-choo train or loop, and I have forgotten the root password. This afternoon I created a boot repair usb stick, but this does not work either. F6 key does not work and I cannot choose the “no mode set”. I fear I might well have to delete the Ubuntu partition (I am on dual boot: windows 7 /Ubuntu 18.4) and try a fresh install, thus losing some data….

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Author: Christophe Naud

Dualboot problem with windows 10 and ubuntu in MSI

I have installed windows 10 and ubuntu 20.04 on my laptop, in general it seems that everything works fine.
The problem I observe, is when I’m in ubuntu, and I reboot to enter windows, there are configurations that are reset, like configurations with the graphic card (nvidia), sound card or wifi.

Similarly, when I’m in windows and I switch to ubuntu, the first time I log in, the wifi card never works in ubuntu, I have to reboot twice for ubuntu to detect it…

I was reading that this may be due to the UEFI configuration, which should be using legacy mode. Should I format the disk, switch modes, and reinstall windows + ubuntu?

Also, in other computers I’ve had, I used to have problems changing the time, when I changed OS, but in this case, I find it curious to observe that not only the hour changes but also the minutes, I don’t know if it’s something also rare.

I’ve put all the problems together because I don’t know if they are all due to the same mistake…

Thank you very much in advance

Pablo

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Author: Pablo MorPal

How to partition hard drive in Ubuntu 20.04

I’m literally brand-new to Linux and Ubuntu, so please forgive my ignorance and bear with me here. I purchased a Dell Inspiron 5593 recently and immediately installed Ubuntu 20.04 on it. Long story short, the keyboard is screwed up, and the place I bought it from won’t service Linux OS. Gotta be Windows/Mac OSX for some stupid reason.

So now I’m trying to partition the hard drive and reinstall Windows on the the partition. I’ve checked out GParted, but I haven’t been able to follow the documentation. For example, I don’t see any unallocated space on my disk, and I’m not willing to unmount my main disk without knowing what that will do to my computer.

Honestly at this point I’m ripping my hair out and would just appreciate some clear instructions on how to partition a hard drive in Ubuntu 20.04 because I’m clearly too technically illiterate to understand GParted’s documentation.

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Author: Yehuda

Easy way to bypass password on my computer

I was not able to formule a question so maybe this was already solved, and if that’s the case, sorry.
But I found a huge vulnerability on my computer. It’s a portable computer with a Win10/Ubuntu 20.04 dual boot.
When I’m logged in, and that I lock my session, this sends me to the login screen, okay. But then, if I do Ctrl+Alt+F3 to go to the terminal mode, and then do Ctrl+Alt+F7 to leave terminal mode, this simply unlocks my session !
It doesn’t work at computer start though, the session must be started and locked.
Note that when I close my computer this doesn’t lock my session even if it’s activated in the settings.
This is a critical vulnerability but it’s doesn’t work at all on my friend’s computer which is also a Win10/Ubuntu 20 dual boot.
I don’t know why this happens to me, any idea of solving this ?

Thanks for you time

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Author: Double Vé

ANSWER

This does not seem to be a normal behavior from what I’ve experienced at all as far as I can remember. I know before I was fond of having my Linux desktop auto-login on startup. I think I also opted to have it login automatically after sleep/suspend. Perhaps the switch to a different TTY/console constitutes as the same behavior. This looks a lot like buggy behavior to me.

I would go so far as to document on how to replicate it, and report it as a bug. Call the attention of the developers so this can be looked into and fixed if necessary.