To add here that the only way I know to go back to a working multi-CPU ubuntu is to remove the 3.18 kernel and let the default be the prior 3.13.43. So I "sudo apt-get remove" the 3.18, and at the end of the command, which executes successfully, I see:
The link /vmlinuz is a damaged link
Removing symbolic link vmlinuz
you may need to re-run your boot loader[grub]
The link /initrd.img is a damaged link
Removing symbolic link initrd.img
you may need to re-run your boot loader[grub]
So I re-run "sudo update-grub", which runs successfully and without error messages.
To add here that the only way I know to go back to a working multi-CPU ubuntu is to remove the 3.18 kernel and let the default be the prior 3.13.43. So I "sudo apt-get remove" the 3.18, and at the end of the command, which executes successfully, I see:
The link /vmlinuz is a damaged link
Removing symbolic link vmlinuz
you may need to re-run your boot loader[grub]
The link /initrd.img is a damaged link
Removing symbolic link initrd.img
you may need to re-run your boot loader[grub]
So I re-run "sudo update-grub", which runs successfully and without error messages.
Perhaps this was part of the boot issue.