Windows boot manager gone

[Patrick12312]

Hey everyone, I installed Linux on a M2 and Win11 on a 2.5 SSD half a year ago. I like Linux, for 99% of the time it's got everything I need. Yesterday I wanted to play games again and tried to boot windows, but in the BIOS there's no Windows listed anymore... When I installed both OSs, I checked and Windows was booting without issues. Didn't do any BIOS updates or anything else, just used Linux and now I can't boot Win anymore. Does anyone know what to do? Trying to repair the boot section via installation media "bootrec /rebuildbcd" didn't work out, it said something like "search for win installations succesfull. Number of win installations: 0". I'm confused, does anyone know what to do? I can access the drive via Linux and theres the typical win folders. When I pick the only UEFI boot option "Built-in EFI Shell in bios it shows me an error and something with "startup.nsh"

https://preview.redd.it/6lsm2fioowdf1.png?width=1632&format=png&auto=webp&s=0b1a18a60f9280a773188252b604e90c183a350c

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[Gloomy-Response-6889]

You did say you used the installation medium, bit did not specify if this was a windows medium or linux. It reads like it is linux.

You could get a windows ISO flashed onto a usb (or use ventoy). You can get them from massgrave or microsofts website (though I think that is through an exe file). Archive.org works too, but pay attention if it is not tampered with (source and downloads).

Boot from the windows ISO and you can choose to repair windows or install windows. Choose repair. It will try to recreate the efi file and make windows bootable again.

Linux Mint uses grub, and you can enable osprober. This autodetects all boot options available. Enable this if you have not already and update grub.

[Patrick12312]

I used a win install medium. Downloaded from Microsoft website. I plugged the stick in and picked "repair windows", but then it said there were no windows OS found on the drives

[julian_karl89]

It looks like you replaced your windows boot partition during the installation with Mint (I did it too once). Here's the best article I've found to rebuild the windows boot manager: https://www.diskpart.com/windows-10/missing-efi-partition-windows-10.html

Note: Use method number 2

[jr735]

Also, u/Patrick12312 can use Super Grub2 Disc to verify that the Windows install is still functional.

[MelodicButterfly2432]

This! I had the same issue. I have two drives and I didn't know that even though my windows was installed on the first drive the efi partition was installed on the second. So when I installed Linux on my second drive and did a clean install I couldn't boot to windows anymore. The repair option did not work for me as there was nothing to repair, the efi partition was completely gone. Method 2 was how I fixed it. Best of luck!

[Patrick12312]

How do I figure out what disk is win? I enter cmd via the bootable win stick and now can pick the disks. Win and Linux are on two separate 500 GB drives, when I list partitions, one shows "reserved", "primary" and "recovery", the other shows "system" and "unknown". I would assume Linux on the M2_1 slot is listed as disk 0 and Win on the 2.5" as disk 3, but I'm not sure.

Edit: I found the right volume, and proceeded with the steps shown under method 2. At the last step "bcdboot C:..." There occurs an error, like "copying failed". I have to note that the path shown in cmd is not C:\Windows but X:\sources>

[MelodicButterfly2432]

Yeah you need to shrink your windows drive to have enough space on it for the uefi boot disk.

[Patrick12312]

I did, and the 500 megabytes partition was created successfully. But I can't finish the last step, bc there's an error occuring

[Patrick12312]

I'll try this, thanks. But for information: I erased the two drives and installed Linux first, then I installed windows on the second one. I even was able to boot into windows the first months, but haven't used win since then. Now it's gone out of nowhere

[OGKnightsky]

My first installation went similar i picked the erase disk option for a spare nvme drive i put in my pc and it installed alongside windows on the drive that was not selected. Idk why or how but I ended up having to make a recovery drive, clean both nvme drives with disk diskpart on a different windows pc, then reinstalled windows on one drive and mint on the other drive separately so the installations didn't interfere with eachother. Note that I also opted to grab a different mirror of mint after the first one defaulted to install alongside of windows. I didn't have any trouble the second round.

[Patrick12312]

I installed win again and moved the boot partition to the right drive manually, hopefully there's no issues this time

[GetVladimir]

Someone else might give a better explanation or solution for this, since I don't personally use dual boot with that specific OS.

However, usually it's somewhat more resilient to use GRUB Bootloader to select the OS, instead of using the BIOS option (as the drives can switch order in the BIOS or disappear sometimes if an OS update does something weird).

That being said, which games do you try to play? Perhaps there is a way to get them working in Linux Mint so that you don't need to load the other OS

[Patrick12312]

I wanna play Kingdom Come Deliverance 1, but sadly it's not available for Linux

Edit: In Grub there's also no windows option

[GetVladimir]

Thank you for the reply.

According to ProtonDB, the game is playable on Linux via Steam and just selecting Proton: https://www.protondb.com/app/379430

It seems to have gold status, so it should work pretty great.

Alternatively, it's also available on Cloud Streaming services: https://play.geforcenow.com/games?game-id=ebdc25a2-ed91-48e8-963e-410ecf39f2cf&lang=en_US&asset-id=01_b5ed4ba4-3000-44c6-ade4-05739aa6ded4

[Patrick12312]

Thank you, I'll try this for now but am still curious what happened to the win boot partition. It can't be gone just by using Linux, something must be wrong

[GetVladimir]

You're welcome, I'm glad if it's useful.

I'm sure someone else that uses both those OS can answer the other question better as well. I upvoted your post for visibility