The installation fails because you have booted the installer in UEFI mode and there is no EFI-System-Partition.
Your workaround describes how to install Grub in the BIOS legacy mode, which works because Grub can be installed into the MBR. First of all, the workaround is not really necessary because you can install Ubuntu in BIOS mode simply by booting the installer in the BIOS mode. (Depending on the UEFI you have and how you created the USB stick, this is not always a simple task) And there is probably another problem, because during the installation in UEFI mode, some Grub packages are removed, e.g. grub-pc. Therefore I am not sure if you have really a complete installation or a standalone Grub, that will never receive updates. Unfortunately there are no log files. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1771651 Title: The installation fails with a "GRUB installation failed" message. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/grub-installer/+bug/1771651/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
