Ubuntu – Dual boot with Windows 10 broken after update

bootboot-repairdual-bootgrub2windows 10

Until a few days ago I had a fine working dual boot with Ubuntu 16.10 and Windows 10, using Grub2. Then Windows decided it needed to perform some updates. After the update, my system booted directly into Windows, skipping Grub. So in order to get back into my Ubuntu system, I created a Boot-Repair USB, and used the default repair option in there. After that, I got my Grub back, and can boot into Ubuntu again. However, now I cannot boot into Windows anymore. If I select the Windows option in Grub, I immediately get an error "cannot load image".

I also tried changing the boot order, to load the Windows Boot Loader first. Then I end up with an error "Failed to open \EFI\BOOT\grubx64.efi Not found"

Some things I tried, based on my googling:

  • run boot repair again -> Makes no difference
  • Disable secure boot in system setup -> Makes no difference
  • Use the Startup Repair option from Windows restore partition -> Gives an error that it cannot repair the startup
  • use rEfind bootloader -> Recognizes Windows, but cannot boot it either

Boot repair info located here: https://pastebin.com/0mPR4bwf

Anyone have any suggestions on what I can try next to be able to boot into Windows again?

Best Answer

I see this question was asked a couple of years ago. Since it comes up fairly high in the search results, I'll put in a late answer anyway. I have a dual-boot Windows/Ubuntu machine that I've been using since Win10 came out. Every major Windows update kills the dual-boot.

When this happens, open a Windows "command prompt" as Administrator. Then enter the following command:

bcdedit /set "{bootmgr}" path \EFI\ubuntu\shimx64.efi

For me, this has reliably fixed the problem every time. Obviously, for other distros, the path may be different. This article provides some good background information.

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