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How To Fix Windows Failing to Start After Recent Hardware or Software Changes

February 13, 2026 4 분 읽기 Updated: February 13, 2026

Dealing with that Windows boot failure message is really annoying, especially when it feels like everything’s out of whack. Sometimes, it’s just a simple thing like external devices messing with the boot order, and other times, it’s actual corruption in boot files or misconfigured BIOS settings. The good news? There’s a bunch of ways to troubleshoot this, and most of them are doable without diving too deep into tech jargon. The goal is to either fix the boot files or make sure your system is reading the right disk with the right settings.

How to Fix Windows Boot Issues: Practical Steps

Remove External Devices and Check Boot Priority

This one often trips people up—Windows gets confused if there’s a USB drive, external HDD, or even network boot options trying to mess with your startup. Kind of weird, but removing all external devices and booting only from your internal drive can resolve this. Sometimes, a system will pick a USB or network boot because it’s set higher in the boot order, even if you didn’t realize it.

  • Unplug all USB drives, external HDDs, SD cards, and anything else that’s not your main drive.
  • Reboot, hit Delete or F2 (or whatever your BIOS uses) to get into BIOS.
  • Navigate to Boot or Boot Order.
  • Set your main drive, like the C: drive or SSD, as the first boot device.
  • If trying to boot from Windows install media, move that to the top temporarily.

Double-Check BIOS Settings: Boot and SATA Mode

If you’ve not checked your BIOS lately, that’s a good place to start. The boot device list needs to be accurate, and sometimes BIOS resets or updates change your SATA mode, which can cause boot issues—especially if the OS was installed with a specific mode like AHCI or IDE.

  • If you’re in BIOS, go to Boot and confirm the primary drive is selected first.
  • Look for options like SATA Mode under Advanced or Storage (sometimes called Storage Configuration).
  • Set the mode to AHCI for Windows 10/11. Old OSes like Windows Vista might prefer IDE.
  • On some boards, switching between modes may require a reboot to test if the system can boot properly with each setting.

On one setup, this switching fixed the issue—on another, it caused a new one. So, it’s kind of trial and error, but it’s worth checking these defaults are correct.

Use Windows Recovery Media to Perform Startup Repair

If your system boots into the Windows Recovery Environment (WinRE), or if you have a bootable flash drive, this is handy. Startup repair can fix common boot configuration errors automatically. And yes, it’s worth trying before going super deep into manual repairs.

  • Create a Windows install media using the official Media Creation Tool, and make sure it matches your OS version.
  • Boot your PC from this USB or DVD. Usually, you need to change the boot order or press a key at startup (like F12, Esc, or F11) to get to the boot menu.
  • Choose your language and agree to license terms.
  • When you see the install screen, click Repair your computer.
  • Go to Troubleshoot > Advanced options > Startup Repair.
  • Follow instructions. It often takes a few minutes, and sometimes, it needs a reboot to finalize fixes.

Manually Repair or Rebuild Boot Files via Command Prompt

If automatic repairs don’t work, it’s time to get hands-on. You’ll need your Windows recovery media to reach the Command Prompt. This is where you can run commands to fix boot sectors, rebuild the BCD, or repair EFI files.

  • Boot into the recovery environment, then select Command Prompt.
  • Check if your disk is GPT or MBR:
diskpart list disk

If you see an asterisk in the Gpt column, it’s GPT; otherwise, it’s MBR. Based on this, follow the respective instructions below.

Fix Boot Files on GPT Disks

  • select disk # (replace # with the right disk number)
  • list volume (find the volume labeled System or EFI)
  • select volume #
  • assign letter = S:
  • exit
  • cd /d S:\EFI\Microsoft\Boot\ (adjust the drive letter if needed)
  • bootrec /fixboot
  • bootrec /rebuildbcd

Fix Boot Files on MBR Disks

  • exit
  • bootrec /fixmbr
  • bootrec /fixboot
  • bootrec /rebuildbcd

Recreate Boot Files if Necessary

  • First, confirm the partition scheme as described above.
  • On GPT disks, assign a drive letter to the EFI partition and backup the BCD, then create a new one:
ren BCD BCD.old bcdboot C:\Windows /l en-us /s S: /f all
  • On MBR disks, just run:
    • bootrec /fixmbr bcdboot C:\Windows /s S:

    Last Resort: Clean Windows Installation

    If all else fails and booting is still impossible, a full reinstall might be necessary. It’s a pain, sure, but it clears out all corrupted files. Make sure to back up what you can before proceeding, especially if you haven’t tried booting into a live Linux disk or similar to grab essentials.

    • Create a fresh Windows install media and boot from it.
    • Choose Custom: Install Windows only.
    • Delete all partitions on the OS disk, then install on the unallocated space. Windows will set up new partitions automatically.

    Use a USB 2.0 Port for Older Windows Versions

    Some older operating systems or USB drives just don’t play well with newer USB 3.0 ports—this part is kind of weird, but it’s true. If you’re trying to install Windows 7 or similar from a USB 3.0 port, Windows might throw an error referencing drivers or compatibility issues.

    Try plugging that boot USB into a USB 2.0 port instead—they tend to be more universally supported for legacy OS installs. If your motherboard has both types, switching to the slower port can fix the “unsupported device” errors. Also, enabling CSM or Legacy Boot mode in BIOS might help if your PC supports it, and you may need to enable USB debug mode or load USB drivers in BIOS for smoother booting from USB 2.0 ports.