I upgraded a VM, which was originally built by someone else, from Ubuntu LTS 12.04 to 14.04. It turns out I hit the same
annoying bug that many others have suffered from:
error: file not found
error: file not found
error: file not found
Press any key to continue...
At least it can be solved with a simple "sudo update-grub" once you're back in. I'm not sure if it's related to the VM being created in VMware and me running it in VirtualBox, but I can imagine this sort of issue could be a big problem for people maintaining lots of servers, especially if it's difficult to get console access to them. I guess there's still a gulf in class between Ubuntu LTS and a more mature long term distribution like RHEL/CentOS. I wouldn't want to run anything other than CentOS nowadays for a typical server.