After installing Kubuntu on my laptop I ran into a ton of ACPI errors upon boot. Kubuntu managed to install most of the Nvidia packages related to xorg and optimus. But it failed to install the main nvidia-driver component. This leads to ACPI errors and a unbootable OS.
TLDR: Launch into recovery mode, install Nvidia gpu drivers.
You will find that Ubuntu launches like normal without ACPI errors. This is only temporary, you will find that screen brightness and many other hardware related functions won’t work.
Launch the terminal.
ubuntu-drivers devices
Then install the recommended nonfree Nvidia driver.
sudo apt-get install nvidia-driver-XXX