Hello Sorry for disturbing and taking from your precious time. After analyzing and reading some links: https://askubuntu.com/questions/789998/16-04-new-installation-gives-grub-efi-amd64-signed-failed-installation-target https://help.ubuntu.com/community/UEFI#Creating_an_EFI_System_Partition I found that I have forgotten to format the first partition to fat32 and set the boot flag and definite it as EFI partition while installing. (I Have started usb live session as UEFI) After I have done this, the installation succeeded. And again sorry, and thanks a lot for the great job you do. So please mark this "bug" report as solved.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1770893 Title: ubuntu 18.04 installer failled to install grub To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub-installer/+bug/1770893/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs