GRUB (Ubuntu) overwrites Windows MBR

Operating Systems & Open Source Linux
1

Hey all,

I just installed Ubuntu on my system on an SSD, and it has overwritten the MOBO to see my Windows 10 installation, which is on another SSD.

Typically this happens the other way around with Windows MBR messing up GRUB, but now the Ubuntu GRUB install has messed up Windows MBR.

Looking at the GNOME disk utility, I can still see the NTFS partition on the SSD with Windows, so I did not accidentally delete it.

sudo update grub does not detect Windows either.

Any help would be awesome, thanks.

2

I can confirm that this does happen, I've run into the same issue. In order to fix it I had to repair Windows with a disc/usb. Then when you go to install Ubuntu there's a certain way of installing that won't mess up your boot options. UEFI has a "feature" which allows it to read a MBR like the old school BIOS used to, but this is not how you want your UEFI to be set up if you plan to dual boot. Unfortunately I can't remember all the details of doing this, but there are guides available online.

3

I didn't think much of it at the time, but when I install Ubuntu when Windows is installed, I usually see a "Install Ubuntu alongside Windows" option, which did not appear here. How bizarre.

Will wait for a few more replies, but I will indeed have to repair Windows likely.

4

Use this

https://help.ubuntu.com/community/Boot-Repair

And if anything else just edit grub and add SDB1 or whatever has your root on it for windows into the list.

5

Any specific options I should pick?

It detects Ubuntu and the two kernels I have installed, but not Windows.

However, what is strange is that on my BIOS screen Windows Boot Manager is back as a boot device, but picking htat just continues to boot to Ubuntu.

6

Fixparts ? http://www.rodsbooks.com/fixparts/ I have use it in the past to fix windows issues coming up through and my first linux install. Not sure if it applies in your case.

7

Then write to grub manually. Not that hard.

8

Not done this myself,dual booting that is, for a while but coincidentally was reading guides to do this today and noticed the need to fix the boot in all of them.

http://www.everydaylinuxuser.com/2015/11/how-to-install-ubuntu-linux-alongside.html

9

There's a program called os-prober which aids GRUB in finding other operating systems -- such as Windows.

sudo apt-get install os-prober
sudo grub-mkconfig -o /boot/grub/grub.cfg
10

I honestly don't know what you mean, if I didn't find it hard I wouldn't be asking for assistance.

11

Thanks for the suggestion, even that didn't find it. I can still access Windows files so I can backup what I need to and reinstall.

Thanks again.

12

No.

Do this.

If you want to use grub, then initialize it with;

bcdedit /set {bootmgr} path \EFI\ubuntu\grubx64.efi

Ignore the armchair expert shitposts.

2 Likes
13

My man, you are a life saver, this solved it for me.

Thanks a ton! :D