ubuntu 16.04.2.LTS was running fine for almost a week - until this morning. When I woke and started up the computer, all I got was a grub command prompt. After a little while I decided to do a reinstall (erase the disk and just install ubuntu). Now I get the above error in the subject. I have run boot-repair tool, disabled the secure boot in the BIOS, learned a thing or two about gparted, fdisk, some other tools, but still no luck booting from the hard disk.

When I press enter I get one option, shimx86. From there if I hit esc or enter I get the error again. For a little while, if I hit esc I got the grub prompt, but that was hours and several reinstalls ago.

Checked for similar threads before posting, some looked promising, but none were similar enough to help.

The latest paste thingy that boot-repair spat out is here: http://paste.ubuntu.com/24148806/

Hoping for some help! Thanks!

Hey bniblet - can you confirm that your computer is UEFI-based ? The bootinfo summary would seem to indicate that. When you reinstalled Ubuntu, did everything go normally ?

There is one particularity in your grub.cfg file that struck me as odd .. : grub is looking for a kernel to boot on sda2 named /boot/vmlinuz-4.8.0-41-generic.efi.signed ... I have never seen the ".signed" extension before. ... Anyone else ?

Indeed this computer is ufei based, even though the paste in file references a mbr. When I run the install, everything goes swimmingly. Then I reboot and find the same error... I am running repair - boot again right now, with a few options changed.

Very hard to help if the ground keeps moving. When you stop changing things post the (latest) boot-repair link. I'll check back in a couple of days.

Just tried boot-repair using the "advanced options", changed a few things I am too exhausted to remember off hand. At some point a dialog said to open a terminal and run 3 commands. The first one was

sudo chroot "mnt/boot-sav/sda2" dpkg-configfile -a

which returned that there is no such directory as mnt/boot-sav/sda2, so I decided to quit out of the repair, and run the 'recommended' version. Tried to reboot from the disk just to see what would happen and got the same error. This time around the pastebin is http://pastebin.org/fzjJWg2x

Also found a couple more instances of 'signed' items for you Rickkkkk in the last command (which I did not run).
sudo chroot "mnt/boot-sav/sda2" apt-get purge -y -force-yes grub *common shim-signed linux-signed*

sorry syg00 I'll give it a rest now and stop changing things!

Thanks for replying guys!

bniblet,

Happy to help if I can.

Looked up this "signed" business ... Turns out it's particular to Ubuntu (at least ...) for systems with Secure Boot. It needs shimx86.efi to function. I found this reference, which may be of use to you:

http://askubuntu.com/questions/88381...ric-efi-signed

Hope it may help.

Thanks for the link Rickkkk. One of the things I changed last time around was to disable Secure Boot, which must be why it wanted to purge the signed files.

Just got back from a little trip. I didn't bring the computer. Anyway I used bootrepair to create another log just now and here's the URL: http://paste.ubuntu.com/24160489/ I am not going to screw around with it just yet so nothing is going to change. Thanks for looking!

Just changed the 'boot' option in the BIOS screen from 'UEFI' to 'Legacy' and booted up just fine. So I guess the problem is solved. Seems like kind of a chintsy solution though. Shouldn't I be able to use UEFI as I did before?

You can, but you have to make sure you create your bootable media (USB drive) using the appropriate steps for both your UEFI system and the particular ISO you are using. It should be more intuitive, but it's not quite there yet ... ;-)

Glad to hear you got it going by booting in "legacy" mode.

Cheers !

I used the same ISO on the same USB drive to install before (and it worked) and it seems to me I was always in UEFI mode up til now. Anyway thanks for checking in Rickkkk.