How to fix it
"Unknown USB Device (Device Descriptor Request Failed)" is a Windows USB error that means the PC detected something on a USB port but couldn't read the device's descriptor — the small piece of information every USB device reports so Windows knows what it is and how to drive it. If that handshake fails, Windows shows the device as "Unknown USB Device" with a warning. In most cases it is a physical or power problem, not a driver problem.
What it means
When you plug in a USB device, the PC sends it a request to report its device descriptor (what kind of device it is, its power needs, its endpoints). If the device doesn't answer correctly — because of a bad connection, not enough power, or a failing device or port — the request fails, and Windows can't identify or use it. The message is a handshake failure, not a missing driver.
Where you'll usually see it
- In Device Manager, under Universal Serial Bus controllers, as "Unknown USB Device (Device Descriptor Request Failed)"
- A USB drive, keyboard, mouse, or printer that won't be recognised
- A device behind a USB hub or extension cable
- An external drive or hub that is drawing too much power
Common causes
- A bad or frayed USB cable
- A USB hub without enough power (unpowered hub, or too many devices on it)
- A failing or dirty USB port
- A failing USB device (the drive or controller is dying)
- A USB controller driver problem on the PC side
Quick fixes (try these first)
- Try a different USB port on the computer — the front-panel ports are often the weakest.
- Try a different cable — a bad cable is the single most common cause.
- Plug the device in directly — remove any hub or extension cable for now.
Detailed fixes
Use a powered hub for power-hungry devices. External hard drives and hubs with several devices need more power than a single port reliably provides. A powered USB hub (one with its own wall adapter) fixes many of these. If you must use an unpowered hub, connect only low-power devices to it.
Reinstall the USB controllers. In Device Manager (search for it or run devmgmt.msc), expand Universal Serial Bus controllers. Right-click each USB Root Hub → Uninstall device (this does not delete your files or programs; it just removes the controller entries). Then unplug the device, reboot, and let Windows reinstall the USB controllers cleanly. Reconnect the device afterwards.
What this does: it forces Windows to rebuild its USB controller and hub entries. It is a local, reversible change and does not affect your personal files. If a specific "Unknown USB Device" entry is stuck, right-click it → Uninstall device, then click Action → Scan for hardware changes so Windows re-enumerates the port.
Check power settings. In Device Manager → Universal Serial Bus controllers, open each USB Root Hub's Properties → Power Management and make sure "Allow the computer to turn off this device to save power" is unchecked. Then in Power Options → Change plan settings → Change advanced power settings → USB settings → USB selective suspend setting, set it to Disabled (on battery and plugged in) and test again.
Update the chipset / USB driver. On a laptop or a system with a specific chipset, install the latest chipset driver from the PC or motherboard maker's support page. Outdated USB controller drivers can cause descriptor failures that a generic Windows driver doesn't handle well.
If the device is dying
If the problem follows the device to another computer, or the device is an old external drive that's also making noises, the device or its controller is failing. Back up anything you can access from another machine, and plan to replace it. A USB device that can't complete the descriptor handshake on every port and cable is usually hardware, not a settings issue.
When to suspect the PC
If many different USB devices fail with descriptor errors on the same ports, the USB controller or ports on the PC may be at fault (a failing motherboard USB controller or a port that's drawing too much). In that case the issue is the PC, not the device — a different USB port on a different machine will confirm it.
Related errors
- 0x80004005 — Unspecified error (can appear around device installs)
- DRIVER_POWER_STATE_FAILURE — a USB or other driver failed a power request
- 0x80070005 — Access is denied