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)
gnome-disks(easier output) orsmartctl. This reads data from the electronics of the drive about the health of your drive. Your question reads like a hardware failure to me (which could be drive failure, cable etc..) This would be my first step(s) anyway.. – guiverc Sep 04 '18 at 07:27gnome-disksand I think I basically see the same as whatfdisk -lshows, just the USB key and a 1.6GB Loop device (I don't know what that is), no sign of the 256GB HDD there. – mm25 Sep 04 '18 at 08:20smartctlwill likely not see the drive. It is BIOS/UEFI that responded to F12 (so it may actually see the drive, but that 'make/size string' is from one ID circuit that usually doesn't operate anything). – guiverc Sep 04 '18 at 08:34LEGACY BOOT,UEFI BOOTandOTHER OPTIONS. For the first two, the 256GB disk and the USB key (when in) are listed as options. So at least there, the disk shows up. I'm afraid I made a mistake when touching the System Setup Option, in that at some point I selected something like "Restore Default System Options", and that maybe explains the change in disk capacity (is that something unrecoverable?). – mm25 Sep 04 '18 at 09:58