I have a DELL Latitude 7480 with Ubuntu 16.04 installed on a 256GB HDD. I usually connect it to a DELL dock station, but since yestarday, after disconnecting and reconnecting it to the dock a couple of times, the computer can't boot correctly anymore [1].
What happens is, first I'm prompted to
a boot window where I'm asked to choose between (paraphrasing)
Ubuntu, Advanced Ubuntu Options, System Setup
and Restore Ubuntu 16.04 to Factory Settings.
If I select Ubuntu, booting starts (the image with the ubuntu logo comes up),
but then I'm taken to a (initramfs) session; after doing "exit" in this
session, I see the warning that goes something like
ALERT! device with UUID=[long string of characters] not found
I tried using a liveCD and that starts without problems,
but if I try to use GParted or fdisk [2], I can't seem to see
my usual HDD. I can only see the USB key that contains the liveCD.
I have also tried to change a bit the System Setup options, for example allowing insecure boot or trying legacy boot, but none of that helped.
How can I regain access to my HDD and restore the correct settings for booting?
[1] Last thing I did when the laptop was working was, when asked Keep this configuration? in Display Settings after connecting to the dock and enabling the external monitor, instead of confirming I closed the window by mistake, and the computer couldn't boot correctly from there on out.
[2] Output of fdisk -l (with liveCD)
Disk /dev/loop0: 1.5 GiB, 1564921856 bytes, 3056488 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/sda: 7.5 GiB, 8019509248 bytes, 15663104 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x000578a8
Device Boot Start End Sectors Size Id Type
/dev/sda1 * 62 15650907 15650846 7.5G c W95 FAT32 (LBA)
