I struggled with the same problem for quite a while, but found a solution now.
The first thing to know is that the Zenbook Prime uses a UEFI-boot mechanism and not a BIOS-based one. The second thing is that the disk is formatted using a GPT partitioning scheme and not the older MBR (Master Boot Record) based one.
This is the reason why there is an EFI System Partition (ESP) on /dev/sda1 on the Zenbook.
The boot-loader should be installed on the EFI partition (/dev/sda1).
Also you need to boot your Ubuntu-disk or USB-stick in UEFI-mode (as you did), since otherwise the installer will apparently be confused and install GRUB to the MBR instead of the EFI partition (it seems to me that the installer should be smarter and detect what kind of disk we have, regardless of how the installation medium was booted, but maybe there's a technical limitation somewhere?).
Finally as a workaround it is also possible to add a custom entry to GRUB which points to the right EFI file.
- First do
sudo blkid and look up the UUID of the EFI partition (/dev/sda1)
- Do
sudo gedit /etc/grub.d/40_custom
- Add the following entry to the file:
menuentry "Windows 7" {
insmod part_gpt
insmod ntfs
insmod search_fs_uuid
insmod chain
search --fs-uuid --no-floppy --set=root 20B1-C9F3
chainloader (${root})/EFI/Microsoft/Boot/bootmgfw.efi
}
Where you replace "20B1-C9F3" with the UUID you looked up in step 1.
Save the file and then run sudo update-grub2.
After rebooting you will see your new entry which should work now.
If you want to remove the other broken GRUB entries from the menu you can easily do it using the grub-customizer program from the repos.
Best Answer
I'm not sure why Nautilus isn't showing the drives. It looks like they're showing up as sdb, so you can attempt to force mount the partitions by using sdb1, sdb2, etc. Assuming you're mounting the first partition, first make a folder somewhere (I'll use /mnt/sdb1 for this example), then run:
Then cd into /mnt/sdb1 and see if the files are showing up. Any error you get will help you diagnose the real problem. I would normally guess here that the filesystem might be corrupt, but that's unlikely to be true for two separate drives.