After running updates a while back, Windows 10 Grub option disappeared. It wasn’t a problem… until today.
At first I received an error about hibernating when I tried to just browse the files. running ntfsfix /dev/sdaX a few times, and i could finally see the files and folders. However nothing I can find will make it re-add to the grub menu.
os-prober returns nothing, with the windows partition mounted or unmounted.
mount -t ntfs-3g -o remove_hiberfile /dev/sda3 /mnt/windows will mount it, but it doesn’t help it find it for grub.
Third, I went to the boot menu of the device (dell) and tried to readd as a UEFI option. However the \EFI\Windows folder is missing. Maybe that’s normal.
I’ve googled and googled but can’t find an answer for this.
Those both need to boot the same way, if you want it to work.
As far as I know, When you boot Windows with UEFI, there should be a directory (in the EFI partition)
\EFI\Microsoft
You appear to have looked for “\EFI\Windows” but that’s the wrong name for UEFI booting of Windows.
If this is a Dell computer, have you tried hitting F12 during boot to get a boot menu from the BIOS? (When I do that, I repeatedly hit F12 during boot so as to have a chance of getting the timing right).
Mrmazda, it shows an entry for windows in UEFI at 0000. However when I try to manually add that entry through bios, the folder is missing from the \EFI folder. Only the opensuse, dell, and another called boot exist.
If Windows bootloader is not present on ESP, it obviously cannot be added to grub menu. You likely need to boot from Windows installation medium and perform boot recovery.
It is possible that copy of Windows bootloader is in \EFI\Boot. You may try booting it.