Ubuntu – Windows 10 (dual boot) doesn’t start anymore!

bootdual-bootgrub2

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?

Best Answer

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.

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