I had a working dual boot system with Ubuntu 18.04 and Windows 10. After my holidays some days ago, the Window 10 does not start when selected in the grub2 menu. Instead, the grub2 instantly appears again.

I run boot-repair (recommended settings) in the hope it would fix the problem. It added additional menu entries for Windows in the bootloader menu:

  • Ubuntu [was here before boot repair]
  • Advanced options for Ubuntu [was here before boot repair]
  • Windows UEFI bootmgfw.
  • Windows Boot UEFI loader
  • Windows Boot UEFI fbx64.efi
  • EFI/ubuntu/fwupx64.efi
  • EFI/ubuntu/mmx64.efi
  • Windows Boot Manager (on /dev/sdb2) [was here before boot repair]

All the Windows entry do not do anything, only the "Windows Boot UEFI loader" gives this ERROR:

Failed to open \EFI\Boot\grubx64.efi - Not Found Failed to load image \EFI\Boot\grubx64.efi: Not Found start_image() returned Not found

Here the report from boot repair.

Do you have an idea about the problem?


1 Answer 1


Create a bootable USB-stick or a CD with the Windows OS

  1. In the Installation menu, navigate to the recover | repair current windows.
  2. Open the cmd.
  3. Enter bootrec \fixmbr and bootrec \fixboot.

That should configure the bootloader for booting the windows operating system, but there's a slight chance corrupting the grub loader.

  • I finally had time to try this. First of all the command bootrec \fixboot doesn't work with the Windows 10 Iso 1803 and gives "Access denied". With the 1703 version I was able to run the commands. I don't get the "Failed to open \EFI\Boot\grubx64.efi" error anymore, but Windows still doesn't start. Maybe it would be easier to install Windows new? Even I have to reinstall all programs again? Sep 29, 2018 at 12:04
  • Yeah, I've already faced this problem. But then I've made a mistake, I've installed the ubuntu in the partition where all the information of the OS stays. Windows actually store it's info. in the other drives also. Sep 30, 2018 at 8:53
  • Then I wasn't be able to manage the grub, so mnaged to open the windows with the above simple commands but not the ubuntu. There the grub loader crashed. If you want to reinstall the windows again, first backup your data from the C drive of windows with EaseUS or Testdisk tools. Sep 30, 2018 at 8:57

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