Windows 10 boot option is gone after installing Ubuntu on a separate HDD

[mekkeron]

Yesterday I decided to make a use of an empty 1 TB hard drive I have in my PC and install Ubuntu 18.04 on it, hoping to get the dual-boot option. The installation was successful, however now when I boot up my computer I'm not getting a boot choice between Windows and Ubuntu, it always boots up Ubuntu by default. First I freaked out thinking that I had accidentally installed it on a primary SSD drive on which I have Windows. But then I checked that drive on Ubuntu file system, all the Windows files appear to be in tact.

 

Does anyone know how can I fix it?

[Mira Yurizaki]

You need to update GRUB (assuming this is the bootloader used) on the Ubuntu drive to include the Windows install. Otherwise, you can, on boot, tell the system to boot from the Windows storage drive.

 

Anyway, if you want to try updating GRUB:

• Open a terminal
• Type in the commands:
  • sudo apt-get install os-prober
  • update-grub
• Make sure after issuing "update-grub" it sees Windows. If it does, reboot and it should give you the option to choose.

[Guest]

Are you on EFI? 

[mekkeron]

1 hour ago, M.Yurizaki said:

Make sure after issuing "update-grub" it sees Windows. If it does, reboot and it should give you the option to choose.

 

It doesn't. Here's the output:

Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-42-generic
Found initrd image: /boot/initrd.img-4.15.0-42-generic
Found linux image: /boot/vmlinuz-4.15.0-29-generic
Found initrd image: /boot/initrd.img-4.15.0-29-generic
Adding boot menu entry for EFI firmware configuration
done

 

[mekkeron]

1 hour ago, Lukyp said:

Are you on EFI? 

Yes

[Mira Yurizaki]

4 minutes ago, mekkeron said:

It doesn't. Here's the output:

Generating grub configuration file ...
Found linux image: /boot/vmlinuz-4.15.0-42-generic
Found initrd image: /boot/initrd.img-4.15.0-42-generic
Found linux image: /boot/vmlinuz-4.15.0-29-generic
Found initrd image: /boot/initrd.img-4.15.0-29-generic
Adding boot menu entry for EFI firmware configuration
done

 

Apparently I forgot to add a step. After installing os-prober, do sudo os-prober then try sudo update-grub

[mekkeron]

1 minute ago, M.Yurizaki said:

Apparently I forgot to add a step. After installing os-prober, do sudo os-prober then try sudo update-grub

No dice. Still getting the same output.

[Mira Yurizaki]

1 minute ago, mekkeron said:

No dice. Still getting the same output.

Does the Linux install even see the Windows storage drive?

[mekkeron]

6 minutes ago, M.Yurizaki said:

Does the Linux install even see the Windows storage drive?

 

Yeah, both SSDs show up in Other Locations.

OS is the one that has Windows 10.

 

[mekkeron]

2 hours ago, M.Yurizaki said:

Otherwise, you can, on boot, tell the system to boot from the Windows storage drive.

I see 

1st Boot Device [UEFI:ubuntu]

2nd Boot Device [Internal ODD Devices]

 

and then under Hard Disk Drives there is:

1st Boot Device - ubuntu

2nd Boot Device - UEFI OS (I assume it’s the Windows one?)

3rd Boot Device - ubuntu

 

So far changing the order of these didn’t seem to do anything. Still goes to Ubuntu all the time

[Guest]

You could use the efi entry instead to boot in Windows, also you could add the efi entry manually in grub too if you want some tweaking

 

also make sure to have the ntfs driver installed, and mount that partition while updating grub, make sure the efi partition is mounted too

[mekkeron]

Fixed it!!

 

It seemed that everything was pointing to the fact that the MBR on Windows SSD somehow got erased, so I was able to recover it by following these steps: https://neosmart.net/wiki/fix-mbr/#Fix_the_MBR_in_Windows_10

Even then I had go through additional steps outlined after "If bootrec utility doesn’t fix it..."

 

After that, I had to change boot priority in BIOS to get to Ubuntu (because after following the steps in the link I provided it defaulted it to Windows) and in Ubuntu, I ran the commands that M.Yurizaki mentioned sudo os-prober and sudo update-grub. It detected Windows right away and I am now able to double boot.

 

Thanks, M.Yurizaki and Lukyp for your help.

 

What a relief, I came very close to reinstalling Windows entirely.