Windows won’t start

'No bootable device' or 'No boot disk found' error

The PC displays a message like 'No bootable device found' or 'No boot disk has been detected' instead of starting Windows. This means the computer can't find a drive with a working operating system to load.

Difficulty
Intermediate
Time
20–60 minutes
DIY cost
$0–$60
Pro cost
$100–$250

Symptoms

  • Message reads No bootable device or similar on a black screen
  • Happens immediately after the manufacturer logo
  • No Windows logo appears at all
  • May follow moving the PC, a power outage, or opening the case

Likely causes

  • CommonBoot drive not detected by the BIOS/UEFIA loose cable or disconnected drive is the most common cause.
  • CommonBoot order changed in BIOS settingsA firmware update or accidental setting change can point the PC at the wrong device.
  • PossibleCorrupted boot partition or boot filesDamage to the small partition Windows uses to start can trigger this exact message.
  • PossibleFailed or dying hard drive/SSDA drive that's failed completely will no longer be recognized as bootable.
  • Less commonBootable USB or DVD left in the driveThe PC may be trying to boot from empty removable media.

What to do

  1. Remove any USB drives, memory cards, or discs and restart, since the PC may be trying to boot from them.
  2. Enter the BIOS/UEFI setup (usually by pressing Del, F2, or Esc at startup) and check that your main drive is listed and set first in the boot order.
  3. For desktops, power off, unplug, open the case, and confirm the drive's power and data cables are firmly connected at both ends.
  4. Check whether the BIOS even sees the drive listed under storage information; if it's missing entirely, the drive itself may have failed.
  5. If the drive is detected but still won't boot, try a Windows installation USB and use 'Repair your computer' to rebuild the boot files with 'bootrec /fixmbr', 'bootrec /fixboot', and 'bootrec /rebuildbcd'.
  6. If the drive isn't detected in BIOS at all, it may need to be tested in another machine or replaced.
  7. Back up any recoverable data before attempting a reinstall if the drive is intermittently detected.

Tools and parts

  • Bootable Windows installation USB drive
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When to call a pro

If the BIOS doesn't detect the drive at all after checking cables, the drive has likely failed and a professional can confirm and help recover data if needed.

Safety

Generally low risk

Generally low risk for a careful person. Stop if anything looks different from what this guide describes.

Related guides

Operator provides AI-generated troubleshooting information. It can be wrong. For safety-critical, electrical, gas, structural, medical, automotive safety, or other high-risk problems, consult a qualified professional.