When I try to boot I get this message:
error: unknown filesystem. grub rescue> _
grub rescue> ls
are as follows:
(hd0) (hd0,msdos5) (hd0,msdos1) (hd1) (fd0)
If you don't know your Ubuntu boot partition, check them one by one:
ls (hd0,msdos5)/ ls (hd0,msdos1)/
When you hit the right one, you'll get a line mentioning "lost+found" and so on.
Assuming (hd0,msdos5) is the right partition:
set root=(hd0,msdos5) set prefix=(hd0,msdos5)/boot/grub insmod normal normal
Now you'll be able to boot into Ubuntu. Once you do, reinstall GRUB:
sudo update-grub sudo grub-install /dev/sda
If you have a UEFI bios make sure you boot through uefi boot and not legacy. Grub is actually there but the bios doesn't allow it to start
The easiest way i found to fix this error was to put in an old windows 98 disk and in dos you can delete and create partitions and then format
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