grub install dev/sda failed

[vineeth reddy]

while im installing ubuntu at the grub istallation step im getting grup install dev/sda failed "fatal error"

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubiquity 2.21.63.6 [modified: lib/partman/automatically_partition/question]
ProcVersionSignature: Ubuntu 4.13.0-36.40~16.04.1-generic 4.13.13
Uname: Linux 4.13.0-36-generic x86_64
ApportVersion: 2.20.1-0ubuntu2.15
Architecture: amd64
CasperVersion: 1.376.2
Date: Tue Aug 6 16:53:24 2019
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper only-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 16.04.4 LTS "Xenial Xerus" - Release amd64 (20180228)
ProcEnviron:
 LANGUAGE=en_IN
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_IN
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)