Recently I have upgraded my Ubuntu PC from 12.04 LTS to 14.04.1. After the first reboot, I was able to boot into rescue mode only (found similar problem here: error: file '/grub/i386-pc/normal.mod' not found). I have upgraded the Grub using
sudo grub-install /dev/sda --root-directory=/mnt
And now I have the following problem: I see the Grub menu, but the default entry is not working, and gave 2 errors
"file not found"
"you need to load kernel first"
But if I go to Advanced options - I see a long list of kernel versions to choose. When I choose "linux-image-3.11.0-15-generic" - it starts to boot.
Why is the latest "linux-image-3.13" is not loading? How can I repair it? And how to detect and remove all unused entries from the grub menu?