Dual Boot: Grub Disappears After One Day

[Rikker1127]

Yesterday I installed Windows 10 Pro on my desktop and then installed AnduinOS 1.4.2 shortly afterwards as a dual boot. Grub was working fine yesterday and I could load both OSs. But now today when I boot the desktop Grub does not appear and the desktop boots directly into AnduinOS. How do I restore Grub?

[Anduin2017]

Hi @Rikker1127,

Welcome to the AnduinOS community, and thank you for trying it out!

What you are experiencing is a known behavior related to how modern GRUB bootloaders handle dual-boot environments. Recently, upstream GRUB disabled the os-prober feature by default for security reasons.

It worked on the first day because the OS installer generated an initial boot menu for you. However, it's highly likely that a background system update (like a kernel upgrade) ran automatically on day two, triggering update-grub. Since os-prober is disabled by default, GRUB rebuilt its configuration, "forgot" about Windows, and hid the menu because it thought AnduinOS was the only OS on the drive.

Here is the exact way to restore your GRUB menu and bring Windows 10 back:

1. Install os-prober (just in case it's missing):
Open your terminal and run:

sudo apt update
sudo apt install os-prober

2. Re-enable OS Prober and force GRUB to show the menu:
Open the GRUB configuration file using the nano text editor:

sudo nano /etc/default/grub

Find the following lines and modify them to look exactly like this (if a line doesn't exist, just add it at the bottom):

GRUB_TIMEOUT_STYLE=menu
GRUB_TIMEOUT=10
GRUB_DISABLE_OS_PROBER=false

(Press Ctrl+O then Enter to save, and Ctrl+X to exit nano).

3. Apply the changes:

sudo update-grub

You should see output indicating that Windows 10 was found. Reboot your PC, and the GRUB menu will safely greet you again!

---

⚠️ A Quick but Important Note from the Dev Team:
I noticed you are installing AnduinOS 1.4.2. Please be aware that the 1.4.x series relies on an older upstream base that is no longer receiving active security patches. Operating it exposes your system to potential security vulnerabilities.

I strongly recommend that you download and install our newly released AnduinOS 2.0.0 from the official website. It features massive improvements in performance, UI/UX (including a brand new Welcome Center), native Xbox controller support, a seamlessly integrated Windows compatibility sandbox, and the latest security patches.

Let me know if the GRUB fix works for you, or if you need any further assistance!

Best regards,

[Rikker1127]

Thank you!