I'm using a HP desktop with Windows 8 pre installed . I turned off fast boot and secure boot and have installed Ubuntu. I can boot into Ubuntu without any problem however I can't boot into windows. When I try it says Error: invalid EFI. So I ran boot repair and now there are multiple options. Some still say the same thing. One goes to a windows menu and gives me the option to repair using a disk but when I use it the computer shuts down. On some of the boot options listed the screen will go black with a blue windows logo in the center and a white "loading" circle under it, I have left it alone for up to 4 hours with it not leaving that screen. And finally one goes to a blue windows looking screen with no text and never loads further, similar to the black screen. Here is the link to my boot repair:


Anyone have any ideas on what's wrong or how to fix it?


You have a boot flag (with gpt that makes it the ESP or efi partition) on the main Windows install. With BIOS that might be correct, but with gpt you should only have the boot flag on the efi partition -sda2. Use gparted or gdisk to change it back to a data partition (remove boot flag). That may be the entire issue with invalid EFI.

Not sure what changes rEFInd may do. But in many cases it is suggested.

Grub2's os-prober still has a bug and does not create correct chain load entries. Do not use any of those as they will not work. But the one's created by Boot-Repair should work or you can try directly booting Windows from UEFI menu.

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