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For a few months now I was using both Linux Mint and Windows 10 through a dual boot setup and a grub loader on startup. Suddenly this morning I can no longer see my grub loader or any boot options and am automatically booting into Windows.

I have checked the UEFI boot options and I can no longer see a grub/Linux option. I currently do not have access to the USB I used to initially install Linux. I am wondering what the best course of action is to recover the grub loader and boot into my Linux partition. I am also concerned that the Data may be corrupted or lost.

Any insight on what to try/how to proceed would be very helpfull. I have read a little about using bootrepair after booting using a USB, but I currently don't have access as I mentioned and would like to see if there are alternatives as I require access asap.

marked as duplicate by Christopher, Rui F Ribeiro, Stephen Rauch, Kusalananda, countermode Aug 14 '17 at 20:27

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migrated from stackoverflow.com Aug 14 '17 at 14:22

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  • AFAIK you must need a live usb to boot repair. – unreleased Aug 14 '17 at 13:45
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    Windows periodically torpedoes dual boot systems with updates that create new partitions. You will need to live boot linux and repair the uefi boot sector from time to time in my experience. – 111--- Aug 14 '17 at 14:30
  • @Christopher The article you linked to only deals with BIOS/MBR. The computer at hand has UEFI firmware, so not a duplicate. – Johan Myréen Aug 14 '17 at 15:01

Windows always overwrite the boot sector when you install it, so you need to reinstall your grub section with:

Find partitions:

fdisk -l

Reinstall into the respective partition:

grub-install --root-directory=/mnt/ /dev/sda

After reboot and update your grub menu with: update-grub

For preventing further issues check if your BIOS have the boot sector protection.

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    The boot sector is not relevant in a UEFI system. – Johan Myréen Aug 14 '17 at 15:02