I'm using the newest 18.10 and only able to boot by going to recovery mode and by resuming to boot from there.
1 Answer
Unable to comment, so asking question here - Have you tried fsck in the recovery mode ?
You could also repair the boot after logging in -
sudo add-apt-repository ppa:yannubuntu/boot-repair
sudo apt-get update
sudo apt-get install -y boot-repair && boot-repair