I'm still suffering from this problem. When installing without internet connection, it would fail with this error messages (attachment 20_05_30.png). Under this state, the /var/log/syslog showed that it couldn't find package "grub-efi- amd64-signed" and "shim-signed", which actually existed in the pool/ folder in the live USB (attachment 20_05_20.png).
I don't think it a GPT EFI-partition problem since I selected "using the whole hard drive" and let the installer automatically partitioned it. The partition table is "Valid GPT with protective MBR", as attachment 20_06_19.png). With internet connected, it would succeed sometimes (but not always). I think the problem is that, when installing grub-efi-amd64-signed it couldn't read the CDROM repository. When internet connected it may find the package in the repository other than the CDROM one. But I couldn't find out why and had no idea about how to solve it. ** Attachment added: "Error messages (in Chinese)" https://bugs.launchpad.net/ubuntu/+source/grub-installer/+bug/1585592/+attachment/4851286/+files/VirtualBox_ezgo_31_03_2017_20_05_30.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1585592 Title: Ubuntu 16.04 - grub-efi-amd64-signed failed to install into /target/ To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub-installer/+bug/1585592/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
