Can not boot to Ubuntu after installing it

Question

I have installed Windows 10 on my machine in UEFI mode. I kept a partition for installing Ubuntu. After Ubuntu was successfully installed, I am not able to boot into it. Bootloader always enters windows 10 without giving me a choice. I tried to change boot to grub but couldn't.

Also, I tried to add Ubuntu in my boot list (under windows) using EasyBCD, but the "Add new entry" section was passive.

I booted windows from usb and run bootrec /scanos which was not able to identify ubuntu.

I tried to switch to legacy mode and install ubuntu. It was again successful. But when PC started to boot in legacy mode it said that there are no any OS detected on my machine.

Can anyone help me to solve this mystery? (without reinstalling windows)

Solution

This is because the BIOS on your motherboard kept Windows as the default option. You can try one of the following in BIOS (F2/F12/Del on startup):

1. Disable secure boot. This will allow BIOS to boot GRUB.
2. Manually change the boot order to boot GRUB first.

Tip: I too had problems getting GRUB entry in Windows Bootloader. But it's easier to get Windows entry in GRUB. So i always boot GRUB first.

EDIT: If after all this, GRUB still does not boot, try repairing it via your Ubuntu startup disk.

Comments

[garyF]

I now realise that Ubuntu's GRUB is signed by Microsoft (wiki.ubuntu.com/UEFI/SecureBoot). So there is no need to disable Secure Boot. (You won't want pesky boot sector viruses.) I install Ubuntu in UEFI mode and change the boot order in BIOS to boot GRUB first. Do NOT use legacy mode if you have UEFI, because Windows 10 keeps updating its shizz, and it might just break your MBR on some fine update day.