Crash and error

[Firdaus Nazri]

I don't know what is wrong. Second time I installing the ubuntu it crash half way at 'grub installer'. Also the first time I installed it earlier, when it finished installing, I proceed press restart and then something weird came out, it's like long list of error and most of 'em said 'SQUASHFS ERROR'. Then I have to force shut down my laptop and when I turn it on again it doesn't go to the grub menu and straight boot to the windows instead even though I've already installed ubuntu earlier. Why is that happened?

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: ubiquity 18.04.14.6
ProcVersionSignature: Ubuntu 4.15.0-29.31-generic 4.15.18
Uname: Linux 4.15.0-29-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
CasperVersion: 1.394
CurrentDesktop: ubuntu:GNOME
Date: Mon Nov 12 22:03:34 2018
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 18.04.1 LTS "Bionic Beaver" - Release amd64 (20180725)
ProcEnviron:
 LANGUAGE=en_US.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 LC_NUMERIC=C.UTF-8
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)