How to Fix Grub After Windows 10 Upgrade
Case 1: Faulty Windows Boot Manager Post-Windows update, Microsoft overrides the Windows Boot Manager to use the NT bootloader. So, now when you restart your system, it directly boots up to Windows 10. This is because the Windows bootloader cannot identify Ubuntu. In order to enable booting to Ubuntu, we would need to make changes in the Windows boot registry. To do that, open the command line with administrator privileges and run the following command.
This would change the bootloader back to GRUB. Now, reboot your system and most probably, you will get the violet GRUB menu.
But, in case you get a “System Bootloader not found” error message, we would need to disable secure boot through the UEFI firmware.
To get to the firmware settings, press F2 or F10 on the boot splash screen. In the firmware settings, disable secure boot. I am using an Acer E5-575G laptop, so my firmware settings would be different from yours. In Acer, you need to set the Supervisor password in order to disable Secure Boot.
Case 2: Faulty GRUB file If the first solution didn’t fix your problem, a possible reason may be that you have a broken GRUB file. In that scenario, we would need to repair the file using a tool called Boot Repair. Now, since you cannot boot into Ubuntu, we would need a bootable USB drive or Ubuntu live CD. You can download the Ubuntu ISO image from the official website and then use a Bootable USB Software to flash the image on the USB. Plugin the bootable USB media or live CD, restart your system and select “Try Ubuntu without installing”.
Once you boot into live Ubuntu, open the command line, and type the following command. The command will add the Boot Repair tool’s repository to apt and also update all the repositories.
Now, we can download the repair tool using the following command
After downloading the tool, run it using the following command. The Boot Repair tool will now automatically scan all the disks in your system to find the ext4 partition. Post that, you will be presented with 2 options. Click on “Recommended Repair” and it will handle all the complexities. If you have dealt with GRUB before and you have an in-depth idea of the Ubuntu file system, you can also select “Advanced Options”. This will provide you more drilled down controls. However, it’s recommended to go with “Recommended Repair” as it mostly solves the problem.
Restart your system and now you should see the GRUB boot menu which will let you boot to Ubuntu.
Wrapping Up
These solutions should fix your problem. There are slim chances that they won’t and in that case, you would have to install a fresh copy of Ubuntu all over again. For more queries or issues regarding Ubuntu and GRUB2, let me know in the comments below. Also Read: How to Disable Incognito Mode in Windows, Ubuntu, and macOS
