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Fix Windows that has Linux that will not boot

We'll restore GRUB, fix the boot order, and repair the boot loader—or tell you when to call a pro.

Troubleshooting · Home maintenance
30–60 min
What you'll need
  • Linux live USB (Ubuntu or your distro)
Step 1 of 4

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Choose the option that matches what you see. You can jump straight to that section.

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Steps

Goal: Restore GRUB so Linux boots in the dual-boot setup.

  • Check boot order—set the disk with GRUB or the Linux UEFI entry first.
  • Good: GRUB appears. Select Linux.
  • Bad: Use a Linux live USB to reinstall GRUB.

Check boot order

Goal: Ensure GRUB is the first boot loader.

  • Enter BIOS, set the disk with Linux/GRUB first, or the “Ubuntu”/“Linux” UEFI entry. Save and exit.
  • Good: GRUB menu appears on restart.
  • Bad: GRUB was overwritten—use live USB.

Reinstall GRUB

Goal: Restore the GRUB boot loader.

  • Boot Ubuntu live USB. Use Boot-Repair (Recommended repair) or manually: mount root, grub-install, update-grub.
  • Good: GRUB restored with Linux and Windows.
  • Bad: Check partition layout or call a technician.

When to get help

Call a technician if:

  • GRUB reinstall fails.
  • Partitions are corrupted.
  • You need data recovery.

Verification

  • GRUB menu appears on startup.
  • Linux is listed and boots.
  • Windows is still available in the menu.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Boot order Set Linux/GRUB disk or UEFI entry first.
  2. Boot-Repair Use Boot-Repair from Ubuntu live USB.
  3. Manual GRUB install Mount root, grub-install, update-grub.
  4. Call a pro GRUB reinstall fails or partitions corrupted.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Boot order in BIOS
  • Whether Windows boots
  • GRUB error message (if any)
  • Steps already tried

Does Windows boot?

If Windows boots, Linux partition may be intact. GRUB was overwritten.

Check boot order—set Linux/GRUB disk first. Good: GRUB appears—Linux may boot. Bad: GRUB is overwritten—use Linux live USB to reinstall.

Yes No

You can change your answer later.

Boot Linux live USB

Create Ubuntu live USB. Boot from it. Use Boot-Repair (Recommended repair) or manually run grub-install and update-grub. Good: GRUB restored—restart. Bad: check partition layout or call a technician.

Yes No

You can change your answer later.

Manual GRUB reinstall

Mount root partition. Run grub-install --boot-directory=/mnt/boot /dev/sdX. Run update-grub. Unmount and restart. If still fails, partitions may be corrupted—call a technician.

Done

Linux boots

GRUB shows Linux and Windows. Select Linux to boot.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why would Linux not boot in dual boot?
Windows update overwrote GRUB, wrong boot order, corrupted GRUB, or failed install. Reinstall GRUB from a Linux live USB.
Can I fix Linux that will not boot myself?
Yes. Boot a Linux live USB, reinstall GRUB with grub-install and update-grub, or use Boot-Repair. Set correct boot order.
When should I call a technician for dual boot?
If GRUB reinstall fails, partitions are corrupted, or you need data recovery. Complex setups may need a professional.

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