Trying to install Ubuntu alongside Windows 10, grub failed to install.

When I try to install Ubuntu 16.04 it gives the error " The 'grub-efi-amd64-signed' package failed to install into / target/. Without the GRUB boot loader, the installed system will not boot. " and then quits.

These are all the steps I can think of. Sorry if the information is incomplete or excessive. I don't understand some of the stuff going on.
-- I have three data drives. I have Windows 10 installed on one, I have tried to install Ubuntu on the other, and the third one is just data.
-- I put Ubuntu to install on a small USB stick using Startup Disk Creator in Ubuntu.
-- When go into BIOS to boot to the USB stick, my computer labels the USB stick as UEFI. It does not label the other two possible boots (the CD drive and the Windows drive) as UEFI. Windows was installed from CD drive.
-- When it installs it says that there is non-UEFI install on the disks, and asks is it OK to force UEFI install. I caot figure out how to do not UEFI install so I say yes, force UEFI install.
-- It says there is no operating system installed, so to avoid destroying Windows, I tell it to customize install Something Else. It says dev/sda/ is ntfs so I assume that is Windows and leave it alone. I tell it to remove all partitions on dev/sdb/ and put ext4 mount to "/" as primary partition on the start of dev/sdb/ and leave small amount of room for swap area. Then I put swap area as primary partition on the rest. For the boot loader at the bottom I tell it to put it on dev/sdb/.
-- When I put in the useame for the install, it suggests as computer name ' useame-System-Product-Name-Invalid-entry-length-16-Fixed-up-to-11 '.
-- While installing, near the end it gives the error " The 'grub-efi-amd64-signed' package failed to install into / target/. Without the GRUB boot loader, the installed system will not boot. " and then quits.
-- Afterwards the BIOS boots are the same as before: USB stick, CD drive, Windows disk.
-- When I try again to install it, it detects Ubuntu 16.04 as installed and finds the ext4 "/" and swap area.

Please advise!