ubuntu install crashed grub not installed amd64 16.04

[Jeriel Jaro]

i am installing ubuntu 16.04 lts on windows 8 on a separarate partition. while installing, it crashed midway saying the grub was not installed (?). im expecting to have the ubuntu successfully install however it crashed and was only to email this using the try version.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubiquity 2.21.63.4 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 4.10.0-28.32~16.04.2-generic 4.10.17
Uname: Linux 4.10.0-28-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.10
Architecture: amd64
CasperVersion: 1.376.2
Date: Fri Oct 20 07:53:20 2017
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 16.04.3 LTS "Xenial Xerus" - Release amd64 (20170801)
ProcEnviron:
 LANGUAGE=en_PH.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_PH.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)

[Phillip Susi (psusi)]

Your EFI system partition is corrupt; you will need to repair it with either dosfsck or Windows chkdsk/scandisk.