Your disk is currently partitioned to boot in bios mode, but you booted
the installer in EFI mode. A warning message prompted you that this
could be a problem and recommended performing a bios mode install
instead, but you chose not to. You either need to perform the bios mode
install, or
I confirm that after creating an EFI partition everything worked. I
consider this to be a bug because the installation software didn't warn
me of the fact that I didn't have an EFI partition.
I followed steps stated here:
https://help.ubuntu.com/community/UEFI#Creating_an_EFI_System_Partition
--
