Recover Ubuntu boot loader after Windows 8.1 installation

Question

I've installed Windows 8.1 after Ubuntu 15. Now there is only one bootable OS and that is Windows 8.1. How can I recover Ubuntu 15 boot loader?

Answer 1

You can use boot-repair.

1. Create an Ubuntu LiveCD or LiveUSB
2. Boot into it.
3. Install the program boot-repair onto the CD or USB.
4. Launch Boot Repair and choose the default repair. It should work fine.

(There is also a more complex method available which involves chrooting into your system, but I personally prefer this one.)

This should work. Just ask if you need any more help :)

Answer 2

To recover Grub (I'm supposing this is the original bootloader)

• Boot through Fedora DVD or Red Hat DVD of Mandriva , not Ubuntu

• Select Troubleshooting and then select Rescue installed system option

• To the question "Do you want to start the networking" say no.

Once you get to the shell enter the following three commands:

1. $chroot /mnt/sysimage

2. $cd /boot

3. $grub-install /dev/sda
   
   

And you have your bootloader back ;-)

Taken from http://www.wikihow.com/Restore-Linux-Grub-After-Installing-Windows