Windows won’t start

A connected USB device is preventing Windows from starting

The PC hangs, shows a boot device error, or behaves oddly at startup, but works fine once you disconnect a particular USB device like an external drive, printer, or unusual peripheral.

Difficulty
Easy
Time
15–30 minutes
DIY cost
$0
Pro cost
$0–$80

Symptoms

  • Boot problems only happen with a specific USB device connected
  • Removing the device and restarting fixes it immediately
  • May show 'No bootable device' or a hang if the BIOS tries to boot from the USB drive
  • Problem reappears each time that device is plugged in before startup

Likely causes

  • CommonBIOS boot order set to try USB devices before the internal driveIf USB is prioritized, an external drive with any partition can confuse the boot process.
  • CommonExternal drive containing old or incompatible boot filesA USB drive that was ever used to install an OS can carry boot sector data BIOS tries to use.
  • PossibleUSB hub or docking station power/detection conflicts at bootSome docks interfere with the initialization sequence before Windows loads.
  • Less commonFaulty USB device causing a driver conflict early in bootA malfunctioning device can occasionally hang the USB initialization stage of startup.

What to do

  1. Disconnect the specific USB device before powering on, and connect it only after Windows has fully loaded to confirm this is the cause.
  2. Enter BIOS/UEFI setup and check the boot order; move the internal drive above any USB/removable options.
  3. Some BIOS versions have a specific 'boot from USB' toggle; disable it if you don't need to boot from USB devices regularly.
  4. If the device is an external drive that once had an OS installed on it, consider reformatting it (after backing up its data) to remove old boot sector data.
  5. For docking stations, try connecting peripherals directly to the PC instead of through the dock to see if that avoids the issue.
  6. Update the PC's BIOS/UEFI firmware from the manufacturer's site, since USB initialization bugs are sometimes fixed in firmware updates.
  7. If a specific device consistently causes this, treat it as incompatible with boot-time connection and simply plug it in after startup as a practical workaround.

When to call a pro

If adjusting boot order and firmware updates don't resolve it and you need that device connected at all times, a technician can investigate a possible USB controller or firmware issue.

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.