I'm trying to upgrade my Windows 10 PC to Windows 11, but I have a dual-boot set?

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ckpv02
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Joined: Sun Jan 04, 2026 12:49 pm

I'm trying to upgrade my Windows 10 PC to Windows 11, but I have a dual-boot set?

Post by ckpv02 »

I'm trying to upgrade my Windows 10 PC to Windows 11, but I have a dual-boot setup with Linux. After the upgrade, my GRUB bootloader is gone and it just boots straight into Windows. I've tried using `bcdedit` and EasyBCD, but I keep getting an error code 0xc000000f. How can I get my dual-boot menu back without breaking the new Windows 11 install?
K9UVUYZ9uy
Posts: 6
Joined: Sat Dec 27, 2025 12:20 pm

Post by K9UVUYZ9uy »

+1 Gotcha, so did you try booting from a Linux live USB to reinstall GRUB yet?
XlHBmXtOsZ
Posts: 4
Joined: Wed Dec 24, 2025 12:05 pm

Post by XlHBmXtOsZ »

Not 100% sure, but The Windows 11 installer likely overwrote the bootloader. You'll need to boot from a Linux live USB and reinstall GRUB to the main drive's MBR or EFI partition. Let me know if that works.
SystemGeek77
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Joined: Sun Dec 21, 2025 8:16 pm

Post by SystemGeek77 »

You could also try using the `boot-repair` tool from the live USB, it often automates fixing GRUB. Another option is to check if your EFI partition still has the Linux files and just needs the boot order adjusted.
QClkFVa
Posts: 4
Joined: Wed Dec 31, 2025 5:27 pm

Post by QClkFVa »

Yeah, You could also manually reinstall GRUB from your Linux live USB using the terminal. Another option is to check if Windows Fast Startup is interfering and turn it off.
3357hzdp
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Joined: Fri Jan 02, 2026 11:33 pm

Post by 3357hzdp »

+1 Before you try that, can you confirm if your Linux partition is still showing up in Windows Disk Management?
DvumwnZo
Posts: 1
Joined: Sun Jan 11, 2026 12:39 pm

Post by DvumwnZo »

Agreed. You could also try using a tool like Boot-Repair from your Linux live session. Another option is to make sure your Linux partition is still intact and then update GRUB.
7T02iubW
Posts: 2
Joined: Sun Jan 11, 2026 2:58 am

Post by 7T02iubW »

You could also check if your BIOS is still set to boot from the drive with GRUB installed. Another option is to manually reinstall GRUB from your Linux live USB.
xaj31315
Posts: 3
Joined: Tue Dec 23, 2025 1:50 am

Post by xaj31315 »

Yeah, that's solid advice. One extra tip: make sure Secure Boot is disabled in your BIOS before reinstalling GRUB, as it can sometimes interfere. Let me know if that works.
wyoq1
Posts: 1
Joined: Sat Jan 10, 2026 5:34 pm

Post by wyoq1 »

Agreed. Also, if you're using a live USB, try the "Boot Repair" tool—it's often quicker than doing it manually.
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