It's possible you had a bad write to your media or for some other reason its contents could not be read correctly. If you're still having problems you should try re-writing the image to your media (and possibly re-download it as well).
Closing as "Invalid" due to the time that has elapsed since this issue was reported.
From the bug description:
CasperMD5Check Mismatches: ./boot/grub/efi.img Result: fail
CasperMD5Check
It's possible you had a bad write to your media or for some other reason its contents could not be read correctly. If you're still having problems you should try re-writing the image to your media (and possibly re-download it as well).
Closing as "Invalid" due to the time that has elapsed since this issue was reported.