Restore the Windows Boot Manager deleted due a Linux dual-boot installation
During a dual-boot Linux installation with Windows, you may accidentally format the EFI system partition containing the Windows Boot Manager files that is automatically generated during the first Windows installation.
In this How-to article, I will explain the procedure to solve the problem by restoring the Windows Boot manager files in order to obtain the dual boot menu with both Linux and Windows.
Once you are logged into Linux, open the terminal and type
This is an example of the output you should get:
| Device | Start | End | Sectors | Size | Type |
| /dev/nvme0n1p1 | 2048 | 690175 | 690175 | 336M | EFI System |
| /dev/nvme0n1p2 | 676048896 | 762165247 | 86116352 | 101,1G | Linux filesystem |
| /dev/nvme0n1p3 | 690176 | 676046847 | 675356672 | 364.3G | Microsoft basic data |
In the example above, the Linux filesystem is located in /dev/nvme0n1p2.
Then we have the Windows filesystem in located in /dev/nvme0n1p3 and the EFI system partition on which we need to intervene in /dev/nvme0n1p1.
In the next steps we will restore the Windows Boot manager files in that particular location.
Let's start by creating an installation media for Windows 10/11, I recommend to use Windows Media Creation Tool.
When the installation media is complete, reboot the device by choosing to boot from the newly created media by changing the UEFI boot order in the BIOS.
As soon as the Windows installation screen appears, press SHIFT + F10 to open the command line interpreter.
Start the disk management tool:
To get the list of existing disks:
| Disk ### | Status | Size | Free | Dyn | Gpt |
| ----------- | ------------- | ------- | ------- | --- | --- |
| Disk 0 | Online | 465 GB | 1024 KB | * |
Select the disk containing the EFI system partition, for example, if the partition is on disk 0:
Disk 0 is now the selected disk.
To get the list of partitions on this disk:
| Volume ### | Ltr | Label | Fs | Type | Size | Status | Info |
| ---------------- | --- | ----------- | ----- | ---------- | ------- | --------- | -------- |
| Volume 0 | C | NTFS | Partition | 322 GB | Healthy | Boot | |
| Volume 1 | D | NTFS | Partition | 102 GB | Healthy | ||
| Volume 2 | FAT32 | Partition | 336 MB | Healthy | System |
Locate the volume with the existing Windows filesystem. In this case C, volume 0
To terminate:
Finally, to copy the boot files from the Windows partition to the EFI partition, we run this command:
You can now reboot and reset the boot settings on the Linux Boot Loader from the BIOS.
You should find the automatically created Windows Boot Manager entry and the possibility to choose between Linux and Windows, enjoy!
References:
How to restore an accidentally deleted Windows Boot Manager with a Windows / Arch Linux dual-boot installation. (2021, June 12). Meroupatate. Retrieved September 25, 2022, from https://meroupatate.github.io/posts/bootloader/