How to Check What Is Plugged Into Your USB Ports
An unnamed device appears in the list, a port is claimed by something you cannot see, or a device works only on one machine. All three are answered by the same device tree.
Quick Answer
Open Device Manager and expand Universal Serial Bus controllers on Windows, System Information on macOS, or run lsusb on Linux. You will see the controller, each hub, and every attached device with a name and status. Unknown entries are common and usually harmless, but stale hidden entries after unplugging hardware are worth clearing.
Listing Devices by Platform
| Platform | Steps | Detail level |
|---|
| Windows | Device Manager, USB controllers, expand each hub | Good, shows devices per hub |
| Windows | USB Device Tree Viewer | Best, shows port, speed and power |
| Windows | PowerShell Get-PnpDevice -Class USB | Scriptable inventory |
| macOS | System Information, USB pane | Good, groups by controller |
| Linux | lsusb and lsusb -t | Good, tree view with rates |
| Linux | ls /dev/disk/by-id | Storage devices specifically |
Interpreting What You See
Hubs behind hubs
Internal root hubs and external hubs both appear. A device buried three levels deep may be sharing a controller with others.
Composite devices
A webcam with a microphone appears as two or more entries. This is normal and not a duplicate.
Unknown device
Usually a device with a missing driver, or a device that failed to enumerate properly. Check the error code before assuming hardware failure.
Hidden devices
Windows keeps entries for hardware no longer connected. They are greyed out and can be removed safely.
Clearing Stale Entries on Windows
- Open Device Manager and choose Show hidden devices from the View menu.
- Expand Universal Serial Bus controllers.
- Uninstall greyed out entries that are no longer used.
- Repeat for other device classes where duplicates have accumulated.
- Reboot and confirm the active list is clean.
Real-World Applications
- Finding which device is saturating a shared controller.
- Identifying an unknown device left behind by a departed colleague.
- Confirming a hub actually enumerates both of its ports.
- Cleaning a machine before handover.
Related Guides
For port capability, read how to check what USB ports I have. For a single port, see how to check a USB port. To test a suspect port, start with is the USB port working.
FAQ
Why do I see devices I have unplugged?
Windows keeps hidden entries for previously attached hardware. Enable Show hidden devices to see them.
Is Unknown device a hardware fault?
Not necessarily. It usually means a missing or incompatible driver, or a failed enumeration that a replug and reboot will fix.
Can I tell which physical port a device uses?
Partially. Windows shows the hub and port number. A dedicated viewer maps that to the physical socket more clearly.
Do these tools show power draw?
Device Manager does not. A dedicated viewer or a hardware USB power meter is needed for current figures.
