When installing Ubuntu you might encounter errors around ACPI or Microcode. We found this to be the case with the Dell Xps. You may see an error similar to:
ae_not_found
The first step to resolving these issues is to ensure you have the latest BIOS. Next, you'll want to install Ubuntu with ACPI turned off. This can be achieved as follows:
Boot from your Ubuntu install disk, and as soon as the Ubuntu screen is shown:
Press ENTER
You'll see the language selection screen:
Press ESC
Move your cursor to Install Ubuntu:
Press F6
This will enable you to add options to the installation command, allow for ACPI to be disabled. Tick the following:
acpi=off and noapic
Now, press ESC and then press Enter. This will allow you to install Ubuntu 17.10 without ACPI enabled and the AE_NOT_FOUND error will no longer prevent you from installing. You can now continue with the Ubuntu installation as per normal.
Note: Once Ubuntu is installed it is strongly recommended that you re-enable ACPI as this is crucial to power management of your computer. These steps are also absolutely crucial to ensuring the correct functioning of NVIDIA cards, and prevent a situation where you're stuck in a bootloop and cannot get to the login screen. To re-enable ACPI execute the following command:
sudo nano /etc/default/grub
Remove the following options from GRUB_CMDLINE_LINUX:
acpi=off and noapic
Save the file with CTRL + O