Ubuntu 4.4.0-109-generic fixed this issue. Seems there were some problems with the Nvidia driver: https://www.reddit.com/r/linuxquestions/comments/7pbro7/ubuntu_meltdown_patch_breaks_system_wont_boot/ But 4.0.0 is a quick fix and to Norbert for letting us know here. Thanks to Ubuntu for their quick fix, Norbert says: “I had defaulted the nouveau driver driving the nvidia card. It was not working””]
Source: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1741934/comments/47