cannot install UEFI grub in /target/ and installation crashed

[alex]

While installing Ubuntu 14.04 LTS on my Lenovo Y50-70 laptop installation crashed.
I selected UEFI installation and manually created two partition ou of the "C" drive of Windows 8.1
one for "/" and one for "swap"
At a point installation crashed because UEFI grub cannot be installed.

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: ubiquity 2.18.8.6 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 3.16.0-30.40~14.04.1-generic 3.16.7-ckt3
Uname: Linux 3.16.0-30-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.7
Architecture: amd64
CasperVersion: 1.340
Date: Wed Jul 8 14:55:03 2015
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed cdrom-detect/try-usb=true noprompt floppy.allowed_drive_mask=0 ignore_uuid boot=casper only-ubiquity quiet splash --
LiveMediaBuild: Ubuntu 14.04.2 LTS "Trusty Tahr" - Release amd64 (20150218.1)
ProcEnviron:
 LANGUAGE=it_IT.UTF-8
 TERM=linux
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=it_IT.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.