I made a bootable drive with Etcher on my Mac. I followed the instructions to erase and properly partition the USB flash drive. It is MS-DOS FAT 32 with a GUID partition scheme.
When I try to boot or check for errors I get the errors listed in the title:
Couldn't get size: 0x800000000000000e MODSIGN: Couldn't get UEFI db list Couldn't get size: 0x800000000000000e
In that order. I have tried on two different USB drives so far. I made sure to eject the disk when prompted to initialize or eject after Etcher finished installing and validating the ISO. The ISO was downloaded from Ubuntu's page. It is 18.04.1-desktop-amd64.iso I am using a late 2011 Macbook Pro Laptop. Is the ISO possibly the wrong format for my device?
Also, when I select the option to boot on restart I get two EFI boot options. Both do the same thing.