I have a Dell XPS laptop (Ubuntu 16.04) and recently tried to boot into it only to find I get dropped into a BusyBox shell with the prompt:
It also says that it cannot find the root UUID in order to boot. So I tried to have a look in /dev/disks only to find it doesn't exist! I thought that there may be a hard drive problem so I ran the Dell diagnostic tool and that returns no errors. Also the BIOS can see the hard drive OK.
Next I ran a live usb of Ubuntu 18.04 and the file manager also cannot see the hard drives. I also checked
fdisk -l lsblk
but they can't see the hard drive either. Checking
dmesg | grep -i error I noticed that there were a few errors some relating to a PCIe bus error. I had a look online and found that there is a known bug (or was a known bug) relating to PCIe bus errors and the recommendation was to set the kernel parameter
pci=noaer. However, this didn't work on the 16.04 installation.
I am totally stumped and was wondering if anyone had any suggestions?
Thanks in advance.
Update: Following the advice of Alvin Liang below, I went into the BIOS settings and changed the SATA operation from RAID On mode to AHCI and I was able to boot into the OS installation.