Grub fails to install when instaling ubuntu from usb to dualboot with windows10

[Kristijan Žic ]

Device: Dell inspiron 7000 13" 2016 edition
Secure Boot disabled
During the instalation from official Ubuntu 16.04 usb stick this error pops up and crashes the installation: "Executing grub-install /dev/sda failed"

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: ubiquity 2.21.63
ProcVersionSignature: Ubuntu 4.4.0-21.37-generic 4.4.6
Uname: Linux 4.4.0-21-generic x86_64
ApportVersion: 2.20.1-0ubuntu2
Architecture: amd64
CasperVersion: 1.376
Date: Wed Sep 14 18:17:34 2016
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper quiet splash ---
LiveMediaBuild: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1)
ProcEnviron:
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
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 dosfsck, or windows' chkdsk.