Well, it says stuff like:
=================== UEFI/Legacy mode:
This live-session is not EFI-compatible.
EFI in dmesg.
Maybe it was booted in legacy mode and not in EFI mode?
It also says:
Warning: /dev/sda contains GPT signatures, indicating that it has a GPT table.
However, it does not have a valid fake msdos partition table, as it should.
Perhaps it was corrupted -- possibly by a program that doesn't understand GPT
partition tables. Or perhaps you deleted the GPT table, and are now using an
msdos partition table. Is this a GPT partition table?
Maybe something is broken? Or it's only a side effect of not booting in EFI mode?
Please someone, convert this answer into a comment :)