Q4OS Forum

Chris33

Member

Registered: 2026-08-02

Posts: 9

Boot loader installation error

Hello,
I want to install Q4OS in a dual-boot configuration with Windows 10. Partitioning and installation went smoothly until I saw this message: “Installation failed
Boot loader installation error
Details:
The boot loader could not be installed. The installation command <pre>grub-install –target=x86_64-efi –efi-directory=/boot/efi –bootloader-id=Q4OS_Andromeda –force</pre> returned error code 1.”
I know, it would be better to remove Windows 10, but it’s my mom’s computer, and for now…
Please, what can I do?

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,291

Website

Re: Boot loader installation error

Welcome to the forum

Here are tips by AI, please follow them and post back.

AI generated:
---
This error usually means that GRUB couldn't be written to the EFI System Partition, even though the rest of the Q4OS installation completed successfully.

A few things would help diagnose the problem:

* Is your computer booted in **UEFI mode** (not Legacy/CSM)?
* Is Windows 10 installed in **UEFI mode** as well?
* Does the EFI System Partition (ESP) already exist, and is it formatted as **FAT32**?
* Did you disable **Fast Startup** in Windows before installing?
* Is **Secure Boot** enabled or disabled?

Please boot the Q4OS Live media again, open a terminal, and post the output of these commands:

```bash
[ -d /sys/firmware/efi ] && echo "Booted in UEFI mode" || echo "Booted in Legacy mode"

sudo fdisk -l

lsblk -f

sudo efibootmgr -v
```

Also, if the installation completed apart from the bootloader, please let us know whether you can mount your installed Q4OS system and whether the directory `/boot/efi` contains an `EFI` folder.

Once we have the command outputs, we should be able to identify the exact cause and suggest the appropriate fix.

Chris33

Member

Registered: 2026-08-02

Posts: 9

Re: Boot loader installation error

Following your response: The system is in legacy BIOS mode, so there’s no EFI or Secure Boot. But Fast Startup was enabled. So I set it to 0 (disabled), then restarted the installation, and it worked! Installation complete!
Unfortunately, after that, I shut down, restarted, and… Windows 10 booted up right away. No access to Q4OS.
I tried this several times, for example by disabling automatic connection, but with the same result. It installs, you can use it, but once you shut down, you can’t get back to it… When I tried to close Ventoy, it displayed the message: “One or more files on this device are open by an application.” Could that explain the problem?

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,291

Website

Re: Boot loader installation error

Could you answer a few questions?

Is there only one hard drive/SSD in the computer?
During installation, where did you install GRUB?
into the MBR of the disk (for example /dev/sda), or
into a partition (such as /dev/sda2)?
After removing the USB stick and powering on the computer, if you press the BIOS boot menu key (often F12, F11, Esc, or F8, depending on the manufacturer), do you see the disk containing Q4OS, and does selecting it boot into GRUB?

If you can boot the Q4OS live USB again, please post the output of:
$ sudo fdisk -l
$ sudo parted -l

That will show us the partition layout and whether Windows is installed in Legacy BIOS mode as expected.

Our guess is that GRUB was either installed to the wrong disk or the BIOS is still configured to boot the Windows disk first. Once we see the partition layout, we should be able to determine the exact cause.

Chris33

Member

Registered: 2026-08-02

Posts: 9

Re: Boot loader installation error

Is there only one hard drive/SSD in the computer?                            YES

During installation, where did you install GRUB?       
into the MBR of the disk (for example /dev/sda), or into a partition (such as /dev/sda2)?

"Configurer la partition ntfs /dev/sda1 avec le point de montage /boot/efi … "

After removing the USB stick and powering on the computer, if you press the BIOS boot menu key (often F12, F11, Esc, or F8, depending on the manufacturer), do you see the disk containing Q4OS, and does selecting it boot into GRUB?

"Boot Option #2 Q4OS_Andromeda (Drive not present)"

If you can boot the Q4OS live USB again, please post the output of:
$ sudo fdisk -l
$ sudo parted -l

I don’t know how to get datas, because of USB VENTOY key. I copy :

fdisk

/dev/sda1    *    500M    HPFS/NTFS/exFAT
/dev/sda2        180G    HPFS/NTFS/exFAT
/dev/sda3        42,3G    W95 Ext’d (LBA)
/dev/sda4        829M    Hidden NTFS WinRE
/dev/sda5        42,3G    Linux

parted

1    1049kB    525MB        524MB        primary        ntfs    boot
2     525MB    194GB        524MB        primary        ntfs   
3     194GB    239GB        45,4GB    extended        lba   
5     194GB    239GB        45,4GB    logical        ext4
4     239GB    240GB         869MB    primary            msftres

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,291

Website

Re: Boot loader installation error

At first, we recommend you to create an ordinary Q4OS boot USB media, see https://www.q4os.org/dqa018.html#creat and install from it. We don't support Ventoy officially, it may go to some unexpected issues.

In anyway check the response by AI, we would quite conclude on that.

AI generated:
---
It actually explains the problem. Your disk layout shows that **Windows is installed in Legacy BIOS mode**, not UEFI:

* `/dev/sda1` is an **NTFS** partition marked bootable. It is **not** an EFI System Partition (an ESP would be FAT32).
* Q4OS is installed on `/dev/sda5` (ext4).
* There is no EFI System Partition on the disk.

This makes the installer message

> "Configurer la partition ntfs /dev/sda1 avec le point de montage /boot/efi"

very suspicious. An NTFS partition should **never** be mounted as `/boot/efi`. That mount point is only used for UEFI installations.

The BIOS boot menu entry

> "Q4OS_Andromeda (Drive not present)"

also suggests that a UEFI boot entry was created even though the machine is using Legacy BIOS. That entry is not usable.

Could you boot the Q4OS Live USB one more time and run these commands?

```bash
[ -d /sys/firmware/efi ] && echo "UEFI" || echo "Legacy BIOS"

sudo os-prober

sudo grub-install --target=i386-pc /dev/sda
```

Please post the complete output, especially from the last command.

If the installer was booted in **UEFI mode** while Windows is installed in **Legacy BIOS mode**, the bootloader cannot be installed correctly. In that case, the solution is simply to **boot the installation USB in Legacy/BIOS mode** (not UEFI) and reinstall. Many BIOS boot menus show two entries for the same USB stick, for example:

* **UEFI: Ventoy** ← do **not** choose this
* **Ventoy** or **USB HDD** ← choose this one

I suspect the installation media was accidentally booted in UEFI mode, while Windows is a Legacy BIOS installation. If so, reinstalling after booting the USB in Legacy mode should solve the problem.

Chris33

Member

Registered: 2026-08-02

Posts: 9

Re: Boot loader installation error

[ -d /sys/firmware/efi ] && echo "UEFI" || echo "Legacy BIOS"
bash: [ -d /sys/firmware/efi ] : Aucun fichier ou dossier de ce nom
Legacy BIOS

sudo os-prober
/dev/sda5 : Debian GNU/Linux 13 (trixie):Debian:Linux
grub-probe : erreur : impossible de trouver un périphérique GRUB pour /dev/sdc2. Vérifiez device.map.

sudo grub-install --target=i386-pc /dev/sda
Installation pour la plate-forme i386-pc.
grub-install : erreur : impossible d’obtenir le chemin canonique de « overlay ».

I try to reinstall without UEFI.

Chris33

Member

Registered: 2026-08-02

Posts: 9

Re: Boot loader installation error

I don't find how to install without UEFI. I arrive to : "Configurer la partition ntfs /dev/sda1 avec le point de montage /boot/efi" and this can't be changed. I tried with Imager. File .exe on USB which arrives in Windows, and there doesn't find the place to install.

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,291

Website

Re: Boot loader installation error

Which Q4OS ISO are you using? Specify the exact file.

I arrive to : "Configurer la partition ntfs /dev/sda1 avec le point de montage /boot/efi" and this can't be changed.

Please post screenshot of that screen.

I tried with Imager. File .exe on USB which arrives in Windows, and there doesn't find the place to install.

We don't understand, what is the failure. Do you have insufficient space ? Or cannot you find Imager shortcut in main menu ? A screenshot with error would be helpful too.

Chris33

Member

Registered: 2026-08-02

Posts: 9

Re: Boot loader installation error

q4os-6.1-x64.r1.iso     I downloaded it yesterday.
I have enough space, but not offered in Stockage by Imager. That's where it goes with q4os-6.1-x64.r1.iso, but without access.
I could try with Gparted to move it out of the partitions Windows, but I’m afraid the system might stop working after that.

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,291

Website

Re: Boot loader installation error

q4os-6.1-x64.r1.iso     I downloaded it yesterday.

Where did you download it from ?
Why don't you install "q4os-6.8-x64.r1.iso" - the current stable Q4OS release ?

Q4OS-imager will burn your bootable USB with the most recent Q4OS .iso release, that's easy and recommended way. Try that way and post the result. If you encounter installer enforce you EFI installation, post a screenshot please.

Chris33

Member

Registered: 2026-08-02

Posts: 9

Re: Boot loader installation error

Oh, no, it was "q4os-6.8-x64.r1.iso", downloaded from https://www.q4os.org.
And as I told you imager-1.7.5.exe can't find the free place.
I don't know how I could copy the screen, but I arrive to this, without opportunity to change anything :
"Créer une nouvelle partition de 43301 Mio sur /dev/sda avec le système de fichier ext4
Configurer la partition ntfs /dev/sda1 avec le point de montage /boot/efi ...
Installer Q4OS sur le nouveau système de partition ext4"
Always the same...

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,291

Website

Re: Boot loader installation error

And as I told you imager-1.7.5.exe can't find the free place.

Run Q4os-imager > click "choose OS > "Q4OS Andromeda Plasma live"" > insert USB stick > click "Choose storage" > select your USB stick > click "Write". You need USB stick with at least 4GB capacity, it will be overwritten with the Q4OS .iso image. If you encounter any error, make a screenshot with your phone and attach it here.

I don't know how I could copy the screen ...

Make a photo with your phone and attach it here or send it via e-mail support@q4os.org

Chris33

Member

Registered: 2026-08-02

Posts: 9

Re: Boot loader installation error

I don't want to use Q4OS on a stick, but on the computer. At the moment as a duplicate of Windows, and on its own as soon as possible.
I send photos with e-mail.

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,291

Website

Re: Boot loader installation error

I don't want to use Q4OS on a stick ...

Q4os-imager will not create USB stick to use Q4OS from. It will create bootable USB stick what you will use to install Q4OS on your computer. Maybe Ventoy enforces Q4OS somehow to think your computer uses EFI Bios. Maybe not, but it's still worth to try to create USB the standard way, q4os-imager, boot, try to run Calamares and look what happens.

We have received the screenshot via e-mail, thanks. If booting as above will not help, we need more debug info to see why your system is recognized as EFI one. Run Calamares installer from terminal:
$ sudo calamares -D8 2>&1 | tee /root/install.log
and attach "install.log" here or ship it via e-mail

Chris33

Member

Registered: 2026-08-02

Posts: 9

Re: Boot loader installation error

Thank you for your attention to my request,
I did create the USB stick using Imager and restarted the installation. Unfortunately, the result is the same. As you can see at the bottom of the attached photo, no matter which option I select, it says, “The EFI system partition on /dev/sda1 will be used to boot Q4OS.” Moreover, at the very top there is an EFI logo and this message: “This system was initialized with an EFI boot environment.” No hope…
I did a twentieth installation anyway, just so I could run the `sudo calamares` command, but as it was finishing up, a slip-up—and sheer exhaustion—led me to start a new installation! Okay, I stop. Too bad for Q4OS.
I don't know how to attach a document, I send the photo by mail.

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,291

Website

Re: Boot loader installation error

TI don't know how to attach a document, I send the photo by mail.

Yes, we have received the photo, thanks. You can send the log-file requested via e-mail as well. We will analyze it and try to figure our what happens.

q4osteam

Q4OS Team

Registered: 2015-12-06

Posts: 6,291

Website

Re: Boot loader installation error

@Chris33

We have investigated a bit and found a possible issue. The live USB may be booted via UEFI (independent of how Windows/the disk itself is set up, a very common firmware default) so Calamares consider partitions as a EFI layout. Please try the following steps and post back the result:
Reboot the Q4OS live USB in Legacy/CSM/BIOS mode explicitly (via the firmware's one-time boot-device menu - pick the non-"UEFI:" labeled entry for the USB stick) so /sys/firmware/efi won't exist, isEfiSystem() returns false, and Calamares does a traditional MBR-style GRUB install matching how Windows itself is already set up - never touching /dev/sda1 at all.