Comment 3 for bug 953959

Indeed it simply failed to boot... What I had to do in a terminal in a live session afterwards, was this:
sudo mount /dev/sda7 /mnt
sudo grub-install --root-directory=/mnt /dev/sda

Then I could boot from the hard disk without any problems. Other operating systems were detected correctly and shown in the Grub menu as well (other Ubuntus, Windows 7).