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
          search --no-floppy --fs-uuid --set=root BC6E-0415
        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

Wifi problems with Gigabyte 570x Aorus Pro WIFI and Ubuntu

Dual booting Ubuntu and Windows causes the WiFi card to not be detected sometimes.

The behavior appears to be random. Sometimes it fully works, sometimes it does not.

After hours debugging I found a workaround that is presented in the answers section.
However I cannot explain why it solves the issue.

This may be related to the problems reported here:

My setup:

Dual boot of windows 10 and ubuntu 20.04 (it appears to also be a problem in 18.04)
CPU: AMD Ryzen 9 3900X
Motherboard: Aorus x570 PRO wifi
Wifi hardware: Wi-Fi 6 AX200

When wifi appears successfully on Ubuntu I can see the following wifi related loaded modules:

$ lsmod | grep iwlwif
iwlwifi               331776  1 iwlmvm
cfg80211              704512  3 iwlmvm,iwlwifi,mac80211

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Author: nico

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


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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

How can I recover files that have dissapeared?

I’m honestly in tears, I’ve just lost 60GB of music I’ve been collecting for over 15 years.

I mounted a drive to /mnt and moved all the music files over to it. When it finished I checked that the files were all there and then shut down my computer and rebooted it into Windows. The files were not there, shut down again and booted back into Linux and they’ve all vanished. I have no idea what to do. Have they actually been deleted?

Any help is hugely appreciated 🙁

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Author: Shaun Wild

No display (only) during GRUB menu

I installed Ubuntu 20.04.1 LTS yesterday on my three year old or so Ryzen powered Lenovo desktop, which has an LG TV connected to it in a dual booting with Windows 10 configuration, but when GRUB loads up, everything about my TV goes dark (no backlight either.) I have BIOS, and I get the Ubuntu loading screen as it boots to desktop. Haven’t messed with Linux heavily since the days of Mandrake 7.2 and have been looking to get back into it, though I have been using it as a desktop for lower powered machines the entire time. (I also used LILO then, as GRUB had compatibility issues. I keep hearing this has not changed and is likely an issue here.) I have followed a few tutorials I found here and there in attempt to get a fairly basic text display or something, so that I can see what option I am selecting, should I hope to go into Windows, though I’ve realized no change in the situation thus far. What are some things I can look for to restore sight to GRUB?

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Author: Roger Gilbert

No ethernet connection available in Ubuntu 20.04

I just installed Ubuntu 20.04 on a clean SSD alongside windows to do C development and when I first booted, there was no internet connection yet my ethernet worked perfectly in windows.

My network controller is the realtek RTL8125 2.5 gb and is labelled “UNCLAIMED” when I run the lshw -C network command. I can access the internet using a USB tether to my phone but nothing I have tried so far has fixed the problem.

Would appreciate any help

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Author: Liam Doughty

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


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.

Ubuntu specific RAM issues – chrome crashing and memtest86 freezing


I’m running 4x8GB sticks of corsair vengeance LPX RAM, a 5700xt and an r5 3600x.

I just installed ubuntu 20.04 a week ago to dual-boot with windows and I’ve been having RAM-related problems. Google chrome pages have been crashing with the aw, snap error: SIGSEGV. Chrome will also completely crash if I have too many tabs open. I ran memtest86 from the ubuntu boot menu and it freezes at 16% on the first pass when I have all my ram in and 35% when only 2 sticks are in (doesn’t seem to matter which two sticks or which DIMM slots, either). I’ve yet to be able to get past 2 seconds into a memtest86 test.

I don’t have these issues when I run windows as the OS and the Windows Memory Diagnostic didn’t return any errors. It seems like the issues come when I try to access more than a certain amount of RAM in Ubuntu but I’m not sure.

The command free -m shows the amount of memory i’d expect.

Does anyone have any thoughts? I’ve tried installing PPA drivers for my GPU and had a look at the latency timings for my RAM in the UEFI but no luck.


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Author: RuddyDev

Displaying Full Storage Capacity after removing Wndows 10 after a dual boot

I’m not able to access the available storage list. It only shows a partial section of the memory leaving out the former memory which had Windows 10 installed in it. I’m sending a screenshot just for clarification.
MY hard-disk contains 500GiB but it says only 135GiB left
Kindly help pls.the image shows the partitions and the notification about only showing 135GiB leaving out the rest of the memory

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Author: Kelvin

Ubuntu 20.04 Does Not Boot


Looks like this one just needs to have their GRUB re-written to MBR again. It’s not so hard. But given that I did something like this 8 years ago… The concept should still be the same. Steps of what I did to fix it here.

I originally had Ubuntu 18.04 installed on my dell xps 13 (2017). A couple days ago, I replaced it with Ubuntu 20.04 due to constant error messages. Until today, I was able to use it without any trouble.
However, I had to use Windows earlier today, and now when I was trying to boot Ubuntu back, I am unable to do so.

First error message

Unexpected return from initial read: Volume Corrupt buffersize 1000 Failed to load image EFIubuntugrubefi: Volume Corrupt start_image() returned Volume Corrupt

and then windows booted automatically.

In trying to resolve the issue,

  1. Tried reinstalling Ubuntu 20.04 using LiveUSB, but got the error saying the system doesn’t have EFI System Partition
  2. Consulted the forum https://ubuntu.forumming.com/question/5394/unexpected-return-from-initial-read-volume-corrupt.
    In running Boot Repair, I received an error message, sayin EFI System Partition is needed.
  3. Used GPart to try to tweak disk settings (changing the disk partition that holds Ubuntu File System from ext4 to fat32… I didn’t document this process very well)
  4. Followed a tutorial that used Windows command prompt and diskpart, creating an ESP.
  5. Reran Boot Repair (successfully this time)

However, now I encountered a GRUB error

“Minimal BASH like line editing is supported. For the first word, TAB lists possible command completions. anywhere else TAB lists possible device or file completions.”

I’ve been looking up different solutions, but I am having trouble understanding them, and afraid I am messing my disk more and more.

Thank you in advance.

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Author: Amanda Jeong