"Prefix not set"-error when a disk has GPT

[Bufeu]

Sorry, Missed that was the answer.

I am out of ideas, but lets run BootInfo and see if it says anything else. It may or may not boot as it has some slightly different configurations.

Post the link to the BootInfo report that this creates. Is part of Boot-Repair:
https://help.ubuntu.com/community/Boot-Info
Boot Repair -Also handles LVM, GPT, separate /boot and UEFI dual boot.:
https://help.ubuntu.com/community/Boot-Repair
You can repair many boot issues with this or 'Create BootInfo' report (Other Options) & post the link it creates, so we can see your exact configuration and diagnose advanced problems.
Install in Ubuntu liveCD or USB or Full RepairCD with Boot-Repair (for newer computers)

But the computer can't even boot with a live-CD without removing the 4TB-disk, and that is the problem.

[oldfred]

Will it boot gparted liveCD or Knoppix or any of the other repair type Linux systems?

http://partedmagic.com/
http://gparted.sourceforge.net/faq.php


http://www.knopper.net/knoppix-mirrors/index-en.html

[Bufeu]

Will it boot gparted liveCD or Knoppix or any of the other repair type Linux systems?

http://partedmagic.com/
http://gparted.sourceforge.net/faq.php


http://www.knopper.net/knoppix-mirrors/index-en.html

Don't know. Should we test that, with the 4TB-disk connected?

[Bufeu]

I don't know how, but I cloned the disc to a USB flash drive using dd, and Ubuntu booted.

[oldfred]

So is it just a defective drive?

Even new drives can be defective.

[Bufeu]

So is it just a defective drive?

Even new drives can be defective.

No, the drive wasn't defective. Ubuntu just didn't want to boot using a CD. Don't ask me why...