I have been running 14.04 on a Lenovo Thinkpad T440p for some time. Today I did a 14.10 upgrade. The upgrade proceeded without any complaints. (I've done many upgrades before, dating back to some really old Ubuntu releases, and they usually work.)
At the end of the upgrade, the system tried to reboot, but I got a flash on the screen of something about a boot error. After that, it wouldn't boot at all.
The main disk is an SDD with 3 partitions: the EFI partition, the
/boot partition, and a partition containing a LUKS encrypted LVM volume. From a live CD, I can mount those and see that they at least look OK.
Is there some process to follow that will allow me to get that drive to be bootable? There are thousands of recommendations to use the "boot-repair" tool, but it has no effect whatsoever (the boot-repair URL for those who care). I've got the laptop BIOS set to boot from UEFI; I didn't change it for the upgrade, but I did check after things went wrong.
edit — (Pointy === Mike McNally btw) I should mention that when I say that the machine "won't boot" I mean that it behaves as if the drive is simply not bootable. The BIOS lets me pick it as a boot device, but an attempt to boot from it gets absolutely nowhere. There are no diagnostics, and no sign that it's even trying to boot.