Use this guide when a USB port provides no power, a device is not detected, or a connection drops repeatedly. Test the device, cable, and port separately before changing drivers. Do not unload macOS kernel extensions or disable every USB controller at once.
Stop first if #
- A port or plug is hot, melted, loose, wet, or smells burned.
- A battery or USB device is swollen.
- An external drive clicks, repeatedly disconnects, or contains irreplaceable data.
- Connecting one device immediately shuts down the computer.
Disconnect the affected device and arrange hardware or data-recovery help in these situations.
Diagnóstico rápido #
- Connect a simple, known-good device directly to the computer without a hub or dock.
- Test the same device and cable on another computer.
- Test another known-good device in the suspect port.
- Note whether the problem follows the device, cable, adapter, dock, or port.
If one device fails everywhere, troubleshoot that device. If every device fails in one port, suspect the port. If all ports fail, continue below.
Safe steps for every computer #
1. Restart and remove extra hardware #
Shut down the computer. Disconnect docks, hubs, adapters, and nonessential devices. Start it again and test one device directly.
2. Check the cable and power requirements #
USB-C cables do not all support the same power, data speed, or video features. Use the cable supplied with the device when possible. Large drives, displays, and audio devices may need their own power adapter or a powered hub.
3. Inspect without inserting tools #
Use a light to look for lint, bent contacts, or damage. Do not place metal tools or liquid in the port. Compressed air can damage a port if used too close or at an angle.
Windows 11 steps #
1. Check Device Manager #
Right-click Start → Device Manager. Look under Universal Serial Bus controllers and the device’s own category. A yellow warning icon indicates an error.
Open the device’s Properties and record the Device status code. Use Microsoft’s Device Manager error-code guidance for that specific code rather than applying a generic registry fix.
2. Install Windows and manufacturer updates #
Open Settings → Windows Update → Check for updates, then review Advanced options → Optional updates for relevant drivers. For a laptop, dock, or motherboard, also check the manufacturer’s support page for current chipset, USB, Thunderbolt, BIOS, or firmware updates for the exact model.
Connect AC power before firmware updates and do not interrupt them.
3. Reinstall only the affected device when appropriate #
For error codes where Microsoft recommends reinstalling the device:
- Disconnect other USB storage devices.
- In Device Manager, right-click only the affected device and choose Uninstall device.
- Do not select an option to delete driver software unless the device manufacturer specifically instructs you to do so.
- Restart Windows or choose Action → Scan for hardware changes.
Do not bulk-disable or uninstall all USB controllers when your keyboard or mouse depends on USB.
4. Review power saving only for disconnects #
If a device works but disconnects after sleep, open its Device Manager properties. When a Power Management tab is present, temporarily clear “Allow the computer to turn off this device to save power,” then test sleep and wake again. Restore the setting if it makes no difference.
macOS steps #
1. Connect the device directly #
Remove hubs, chains, and adapters where possible. Confirm that the device is powered and that its cable supports the required connection.
2. Approve new accessories when prompted #
Mac laptops with Apple silicon may ask you to allow a newly connected USB or Thunderbolt accessory. Review System Settings → Privacy & Security if the prompt was dismissed.
3. Check whether macOS can see the device #
Hold Option while opening the Apple menu, then choose System Information. Select USB or Thunderbolt/USB4. If the device appears there but not in its app, update the app and device firmware. If it never appears, retest the cable, adapter, and another port.
4. Update and restart #
Install current macOS updates from System Settings → General → Software Update. Restart with nonessential accessories disconnected.
Do not use kextunload, kextload, or commands that disable sleep to repair USB. Modern macOS protects system extensions, and forcing a USB kernel component to unload can disconnect input, storage, or other critical devices.
5. Use model-specific power guidance #
Apple silicon Macs do not require an SMC reset. If an Intel Mac has a confirmed power-management symptom, use Apple’s SMC instructions for that exact model; there is no single key sequence for every Intel Mac.
Verify the repair #
Reconnect one device at a time. Confirm that it appears in File Explorer, Disk Management, Device Manager, Finder, Disk Utility, or System Information as appropriate. Copy a small noncritical file to and from a storage device, then safely eject it.
If the port still fails with multiple known-good devices and cables, the port, internal connector, or controller may need hardware service.
