---
title: "Windows/Ubuntu dual boot issues"
url: https://michalasobczak.pl/posts/windows-ubuntu-dual-boot-issues.html
author: "Michał Sobczak"
description: "I have dual boot on my Lenovo Thinkpad T420s, Windows 10 and Ubuntu 22. Actually I had, because I tried to reinstall Ubuntu 22 and I’ve lost my dual boot and ability to boot at all."
published: 2022-11-01T20:23:33.000Z
updated: 2022-11-01T20:35:03.000Z
language: en
categories: ["Technology"]
tags: ["Ubuntu", "Windows"]
license: CC BY-NC-ND 4.0 (https://creativecommons.org/licenses/by-nc-nd/4.0/)
---
# Windows/Ubuntu dual boot issues

I have dual boot on my Lenovo Thinkpad T420s, Windows 10 and Ubuntu 22. Actually I had, because I tried to reinstall Ubuntu 22 and I’ve lost my dual boot and ability to boot at all. So I tried few things:

-   reformat manually EFI and root partitions
-   os-prober and update-grub
-   setting root and prefix at grub rescue
-   grub-install
-   Windows installation troubleshooting

Unfortunately it does not work. Something went terribly wrong. To bring back Windows first boot from installation media and go for command prompt:

```text
diskpart
list disk
sel disk X # select disk with Windows installed
list partition
sel partition Y # select boot partition
detail partition # in case Active is set to No then...
active
exit
```

This way I was able to boot into Windows once again, but unable to do it from grub and unable to boot Ubuntu any more. I also tried the following:

```text
bootrec /fixmbr
bootrec /fixboot # does not work
bootrec /rebuildbcd
```

So I decided to reinstall Windows as I keep only Office, Typora and Fruity Loops there so will be easy to bring it back. After Windows reinstallation I tried to install Ubuntu one more time, but… there is no option for dual boot installation! Why? I do not know for now.